Most of the time I've directed, I've also sung.

Usually, in most groups it has been a necessity. With chant, I can guide tempo and phasing more effectively. With polyphony, usually we are lacking basses or the strong lead.

Secondarily, as Chris mentions above, it is hard not singing - who can hear Guerrero, Palestrina, Victoria and not instinctively want to sing?

However, there is a definite trade-off... and when I feel I don't have to sing, I try to avoid being selfish about what I want. When I sing, I can't do the same justice to hearing the other parts and correcting issues - I have to rely on section leaders to assist by pointing out areas that need review. That mostly works, but there are things that fall through the cracks.

The other issue is that between directing and singing, breath control starts to become compromised.

The more I can back away from singing, the more that forces the group to become functionally independent.

From a choristers perspective:

I've sung in choirs where the director sings of necessity. Normally this practice has been helpful. I've been in choirs where the conductor sings for fun. Normally this practice has been unobtrusive. I've been in choirs where the conductor sings directly at the section, sometimes the individual, who needs help. As much as I would love to see that practice succeed, it rarely does.

I do, and because we are few in number

but I also love singing and would be sad to lose any opportunity to sing.
that said, I agree with a lot of the issues which have been mentioned by others.

I don't really sing all that much, but I play and direct - that seems to amaze another DOM in town that I know. But I have done it for years to the point of not even thinking about it anymore. Occasionally, I will sing too if we are short on people, or I need to emphasize words for the choir.

When I sing (rarely) I direct only in a psychological sphere as waving arms only destroys the acoustic. However, I might use small gestures for important cues. I gather the schola into a semicircle when doing so and that helps with cues also.

I think you develop the skills you most need. If you need to direct and sing, you will do so. If you need to direct and play, you will also do so. If you need to direct, play, and sing - ask for more money.

I sing and direct, out of necessity. I’m the only strong soprano and really only a mezzo at that, but I’m slowly becoming the high soprano my college choir director told me I would be if I practiced singing every day. Funny how things work out like that. Basses are on their own if they have a solo passage, though. I’ll help in my octave during rehearsal, but obviously can’t during the service. I’m really thankful they’re good, strong, and do just fine without me LOL

Agreeing with CharlesW - Irish is in line for a raise!! :)

When I sing, I can't do the same justice to hearing the other parts and correcting issues - I have to rely on section leaders to assist by pointing out areas that need review. That mostly works, but there are things that fall through the cracks.

IMHO directors whom I've witnessed singing along, are not doing it out of necessity, even if they may have convinced themselves that it is. I think it's a bad habit. It makes it nearly impossible for the director to hear balance for one, but every other issue, especially.

Yes, most of us love to sing. Most orchestra directors also love whatever their instrument is, but except for very rare cases, you don't see them up there playing anything. Because that would be ridiculous, wouldn't it? Unfortunately, it really isn't supposed to work that you are the musician and the director, too. (The "leader" of a small ensemble is obviously not the same thing as someone standing in front of an ensemble, conducting.)

While I find it easier to believe that a male director's voice might be a necessity, a female director has (I believe) much less of an argument.

First off, If the ladies who sing the same part as the director cannot sing their own part unless she sings as well, that's a big problem that needs to be addressed and corrected.

Also, not only is the voices going separate ways much less than ideal (even with a microphone), but the subtleties of entrances and such get incredibly sloppy when the director could be more focused on his or her own entrance, than making sure that the conducting is clear enough for everyone to enter at that exact same time, and so the director might actually be singing the slightest bit ahead of everyone else.
I know others in this group are orchestra musicians. The subtle difference between the baton and the played beat is something that not everyone notices, but it plays into the latter issue.

(TBH, oftentimes, I find organists distracted from the ensemble mentality if singing whilst playing, as well.)

I did say it was a "rare," not nonexistent, occurrence.
They're also the stars of their shows, not [humble] members who need to appear and sound as one within their ensemble.

As I said, this is my honest opinion.

Singing along with something such as a response, hymn, or even leading a chant--in short, anything monophonic--is okay in my books. But I still stand by my statement that, in any kind of polyphonic or intricate music, it's a hindrance more than anything.

I switch off and on. Back when the choir was just getting started and everything was unison, I would softly sing (or lip sync) because it helped some choir members know when to start/stop at places. Then when we began singing in harmony, I would sing bass because the men were too few. Now I tend to sing tenor because that section needs the extra help. I would prefer to not sing while directing/playing.

In my present situation that is typically short of men, I sing more than is good for the choir. Ideally, the choir should stand on its own because the conductor's podium is seldom an acoustically good spot from which to sing, and while the conductor is singing he cannot hear the choir very well. This last is especially bad in rehearsals. Sometimes it is necessary, but it is not ideal BTW, I love to sing, also.

I think of a conductor (at least of singers) as I do a headmaster. He's a singer who happens to have command authority. Directors (at least of singers) who don't sing are like heads of school with no teaching experience.

I sing and play (guitar, or as my username suggests, banjo... which is falsely maligned as an instrument of the devil... but that is another topic!), and direct as best I can with shoulders, head, and facial exprsssion. It’s a small choir, not highly trained but deeply devoted.

I call our organist "Bobble Head" when he is forced to both direct and play at one time.

Also, how are a banjo and a law suit alike? In both cases people are relieved when the case is closed.

If left to my own devices I wave my own hand around while singing. I swear I sing better that way. I think the hand and vocal centers in the brain must be very interconnected.

When in a group, I want someone to direct, lest we all sing as we please and not start and stop at the same time. At least do gestures at the stops and starts!

But one crazy-maker: a couple times I've been in a group where the keyboardist sang intermittently (bits and pieces of phrases, a word here or there). It's SO distracting! Her entrances startled me. Her pauses confused me. Did she want us all to stop, too? Why did she start singing there? Were we off? I never did figure it out, so just tried to keep track of her with one eye while reading lyrics and watching the other singers with the other eye.

...and excoriate...

With all due respect to Mr Hawkins, whom I hold in genuine esteem -

I have never had or been in a congregation that had trouble starting and stopping together, with or without the organ. Directing congregations is as tacky as all get out. Choirs need to be directed because their music is more artful and more complex. I've even known congregations who would begin parts of the ordinary and the dialogues right on time and right on pitch without so much as a note from the organ. This is accomplished by osmosis and experience. I've had congregations whom I could have sing a hymn stanza a capella by simply not playing and they would unerringly begin and end together a capella. Directing congregations is as tacky and unnecessary as all get out - it is also insulting, very insulting, to the people, and a visual blight on the flow of ritual. Only Baptists and Catholics seem unable to sing without pirouettists and arm flailers making narcissistic spectacles of themselves. The rightful and only 'director' of the congregation is the organist.

any cantor who attempts such

As far as I've been able to tell, it isn't that they need a prompt to sing. What they need is to hear the cantor/choir begin, to make sure they're singing the right thing - for it isn't as though every verse ends on the beginning pitch or interval of the responsorial.

That, and/or they simply forget the response between iterations (tends to happen at daily/spoken Masses), because of the verses. No amount of arm waving will conjure up words that have already slipped from their memory.

----

I swear I sing better that way.

While this could very well be so, the director's job isn't actually to sing, but to lead.
Their voices should not be crutches.

This past Sunday, the ladies sang a trio, with 2 of our sopranos singing 2nd soprano. Since 1 of the young ladies who would have been singing 1st didn't show up, it was left just another young lady and to our director. The young lady started freaking out, and saying, "well, then we'll just see what comes out, because I can't hear [the director] from here!"
Choir members absolutely should not be relying on hearing the director in order to sing their part correctly/well. We all need to be encouraged to learn our own parts, and directors should be encouraged to listen more, that they may hear deficiencies and intonation issues, that should someone become sick, the entire choir doesn't fall apart because of his/her absence.

Regardless, I've already posted about my opinion on the general topic previously, in this thread.

My ideal would be very like what the Cathedral of Our Lady of Walsingham has achieved*. And I agree that if the organist can be the directing influence no other direction is more desireable. Unfortunately this ability is in inadequate supply among organists. Similarly the ability to lead the congregation simply by voice and personality is uncommon among cantors.

GIRM 104. It is fitting that there be a cantor or a choir director to direct and support the people’s singing. Indeed, when there is no choir, it is up to the cantor to direct the different chants, with the people taking the part proper to them.

However the organist is mentioned in the preceding paragraph, indirectly including their rôle in the singing.

103. Among the faithful, the schola cantorum or choir exercises its own liturgical function, its place being to take care that the parts proper to it, in keeping with the different genres of chant, are properly carried out and to foster the active participation of the faithful by means of the singing. What is said about the schola cantorum also applies, with due regard for the relevant norms, to other musicians, and especially the organist.

* In the one priest parish I now live in, with a typical Sunday congregation of less than a hunded, we will probably never have the resources.

"rôle"?

Leona Helmsley had something to say about that:

https://izquotes.com/quotes-pictures/quote-we-don-t-pay-taxes-only-the-little-people-pay-taxes-leona-helmsley-82760.jpg

https://izquotes.com/quotes-pictures/quote-we-don-t-pay-taxes-only-the-little-people-pay-taxes-leona-helmsley-82760.jpg