It's really gonna have a lot to do with how well your personal voice holds up. It's not a one size fits all sorta thing.
I actually gig and sing that much myself and I rarely have problems.
But a lot of singers will ...... so it's gonna be a matter of how yours does and you'll just have to see.
Personally, most of my gigs are 4 hours and I like to take 2 twenty minute breaks. I HATE that 45 and 15 thing ..... it just makes the night drag by for me. It's not unknown for me to go 4 hours with only one break if people are around and it's a party.
On a 3 hour gig, as you're gonna do, I would typically play 90 minutes, take one 15 minute break and that'd be all. .
But, once again ..... if it's happening, I'll frequently go straight thru with no break at all.
But for me, a 3 hour gig is short. I'll often do two 4-hour gigs in a day
bdenton has it right though ....... the industry standard in clubs is an hour on and 15 minutes off. On my own gigs I NEVER do that ....... 45 minutes just gets me and the crowd going good so I try to never a set less than an hour and twenty.
But it's just so voice dependent ...... I'm lucky in that I rarely have vocal problems but that's just luck ..... not anything wise that I do.
