I like to do full takes then get the best bits off playlists.
A lot of singers I work with like to do all the verses or chorus only. Then move on to bridges etc.
A few like to do lines only so if 4 lines in the chorus one at a time. Or every second one so it give thems more time to breathe.
A few like only a line at a time.
Personally I hear the cut ups more if they do lines or a couple of words at a time.
I also try to get singers to sing into the drop in.
A lot do not want to.
It's not as bad as auto-tuning.
Although normally guys you comp a lot for you autotune