Hi there.....10-15 minutes is more than enough for a drink + to splash around. Sometimes if they have poo caked on themselves it's good to soak that long, then it's easy to clean off with a toothbrush. It seems that some beardies enjoy their
bath, others tolerate it and yet others hate it.
The things to be careful of with a very long soak is that they don't aspirate water [ especially babies ] or that the water doesn't cool off . Being cold blooded it would really chill them and be pretty unpleasant,so for a soak that's longer than 10 minutes it would be good to add extra warm water .