I haven't done a big cleaning yet but my jacksonii has moved a few times to newly decorated enclosure and my panther I only have a few weeks...
My jacksonii doesn't make a big mess so I think I'll just clean all branches thoroughly every 3 months and doing daily upkeep like cleaning dead feeders and leaves...
My panther will be a different story, he eats a lot and poops bigger so I'll probably do him ever other month.
Easiest way for me would be to take out the plants and put cage and wood in the shower for a good scrubbing.
I'm not sure yet, I mist 15minutes a day, I don't see a lot of dirt build up on wood and branches because of that.