Autotune is one of those assumed evils of modern recording. And while I hope that you have the pleasure as I have, working with artists who can make an A+ vocal performance without “sending it to the cleaners” most often some vocal tuning will need to be done. And frankly I have no problem with that. After all, is it any more honest to sing a line over and over until it’s finally right as opposed to a brilliantly sung first take which needs just a bit of help in a spot? Ok...that’s my argument on tuning. You can of course disagree...but you better have a good vocal to back it up..
But if you use it, you of course don’t want it in while recording. And you really shouldn’t have it in during the comp process. You really need to hear the vocal naturally so you’re hearing the best lines as they are. You may want to check a great line with the tuner in to see how it changes the pitch in order to help you make a decision, but in general, you’ll make better choices by leaving it off.