I'm lucky enough to do this for a living.
I have a Christmas show, a New Years show, an Easter show, St Pat's, kids programs, 20s and 30s swing for playing the wine tasting rooms, old time Cowboy songs and poetry, Halloween, material for Old Folks homes and school programs and more. There is some overlap, but these are very different situations calling for very different material.

Of course I rehearse everything I'm planning on doing for any given show, but it is hard to keep all of it word perfect in my head. Life is busy and sometimes I don't get all the rehearsal time I'd like. I used to haul around several binders, or rather, the binder I needed for any given show. Heavy, awkward, and my music stand would sag from the load. Now, it all fits on my iPad. Light, easy to use, and it works. If I get a request for something I had not planned on, if I have it, I can do it.
It took a while to get files transferred, and to learn to use it, but I absolutely recommend it.

625 songs and poems on an iPad organized by Onsong.

It's a magic world.