I'm hoping that this thread isn't morphing into a reader vs. non reader thing. I was basically interested in how many of us read during gigs. I can read but I cannot sight read on a gig. I can read chord charts on gigs if needed. However, I prefer to learn by ear and memorize. Nothing more, nothing less. Let's not turn this thread into anything more than that, please.
Fair enough. I think it really depends on the gig. If you're in a cover band that plays the local spots, probably reading isn't going to come anywhere near that gig. Though, because I can read, I have sub'd in a few bands. They gave me the set lists a couple of days before, with some alternate songs that might get called out, and I charted them myself. It's an easy way to play 3 hours of music when you know you won't be getting any rehearsal time with the band.
If you're playing in a Jazz band, reading is probably going to happen about 75%+ of the time. Some people just want to do standards and a lot of guys just memorize them (I've played "Chameleon" so many times I can fall asleep during the song and wake up after it's over.). Some are going to want to do some deeper tracks and you'll probably need a Real Book or something similar. You'll, at least, be reading chord charts. There's a misconception that reading makes you less able to improv. That is just not true. Improv is a totally different muscle that needs exercise like anything else. Jazz bands will have you reading... then tell you to take a solo. At that point, you're only figuring the measures and chords... notes on the paper be damned.
If you're doing the Broadway stuff (musicals), you're going to have to get your reading chops up to snuff. Those band directors want and need you to be able to read and you'll have cue-notes scrawled all over some of those charts.
It used to be, if you were going to be a studio musician, you had to read. Now, they don't care as much (we circle back to fewer musicians making music). They'll just play you a song and, if you get the feel and chords of it, they'll just let you have at it.
I've done some radio work. Some guys were more of a producer type and couldn't read music to save their lives. I had to make quick charts, on the spot, so I could get the cues the directors wanted me to pick up on. Other guys had music written out. Because I can read, I have been asked to play the bass and guitar parts. Getting double pay does not suck. Plus, primarily being a bass player, I have a sense of timing and rhythm... unlike most guitar players.