why are u getting demands to learn 10 songs for the next day? that seems a bit inconsiderate of your time. and that just sets u up to be unprepared in rehearsal. a bit unfair if you ask me.
what i do is upon first learning the song, i commit it to memory. so most songs we do, i remember the patterns (but not always the key). Its easier for songs that follow a progression, but for ones that have a specific bassline or run thats key to the song, its a little harder. What i try to do is keep a few playlists on my iPod, and at work, during my commute, and free time I just have those playing. More than likely the rotation will include songs that we will do, and stuff that i feel i just need a refresher on, i'll cue up. Sometimes i'll go through different songs during free practice and just brush up on old stuff.
i tried the chart thing. too many papers. and it gets cumbersome trying to chart out stuff when i dont know what the heck the other instruments are playing. so it cant be a chord chart, and i hate bass tabs. also songs that have crazy timings, or numerous moves are easier for me to remember than write down.
oddly, i like relearning songs. i actually do that intentionally once i feel my skills have progressed a certain level. i get to try stuff new and even discover new things in the song that were over my head the previous time.
5deep, i suggest figure out your learning style and adapt. You've gotten several different ways to handle the same task, but you have to explore and figure out what works best for you.