The last gig I played on bass, I was stood right over my amp, and the soundman had me turned down so low I actually couldn't hear what I was playing. Apparently the sound was perfect out front (it was a very small room, quiet audience) so I was happy. I just had to trust that I knew how to play the songs.
Regarding drums - I play a lot of gigs on drums and I've never had to resort to hot-rods, I just don't hit the drums as hard. The big one is the crash cymbal or open hats which can get very piercing if I get carried away. I put ear plugs in for the loud gigs (big room and PA) and don't wear them for the quiet little pubs, so if I play too loud, it hurts. It's like my own sound level meter. Everyone else in this band just keeps to a sensible level over the drums, so we really don't care if we get a soundcheck or not. If it's one where you're asked to turn up 5 hours before playing to check, I'll decline and just wing it.