I use crib sheets when I'm learning a song. But the only kind of "crib sheet" I use when singing for others is a set list of song titles taped to the side of my guitar. By the time I sing the songs before any kind of audience, I have them thoroughly memorize and don't need crib sheets.

It's not that difficult. Once committed to memory, I can turn my attention to the nuances of the song itself, without the distraction of three-ring binders, handsful of paper (not too convenient when accompanying oneself on the guitar), teleprompters, cue cards, or tablet computers.   

I'm essentially retired now, except for "hoots" (informal get-togethers and song fests with friends), but over about fifty years I did coffeehouses, concerts, television, folk festivals, benefits, a whole variety of musical events.

If I expect audiences to want to listen to me, I owe it to them to know the songs.

I don't do karaoke or similar stuff….

Don Firth

P. S. If anyone on this thread is interested, I can post some tips for memorizing songs and keeping them fresh.