My son gets a bath every other night before bed. On the off nights we wash his face and hands with a wash rag. Obviously if he goes and plays outside and gets muddy (of slips and falls in puppy poop and gets it all over him like yesterday, ugh) he gets a bath right away, no matter the time of day but on a typical, uneventful day it's before bed. We used to give him a bath every night but his hair was getting really dried out and since my husband and I are on opposite shifts there's only one of us home at a time and the nightly baths were getting exhausting.
Before bed if they're not too filthy... but most days they're head-to-toe in mud, dust, soil, mucky water, or goat/horse hair and dirt. So those days they get a bath when they come in for the night, then just wear their PJs to dinner and the rest of the night.