I think this depends SO much on the type of tray, type of litter, how often the cat(s) use it.
If I was using the wood pellet stuff and the tiny open trays they have up at our local rescue centre, I'd be doing a full clean every day or two I reckon.
But I use World's Best in very large trays with hoods/lids on them. And almost never do a full clean out. Like, once a year... and when I fully empty is the bottom is honestly totally clean. Feels like such a waste with such expensive litter.
We scoop morning and night, and during the day if we notice that somebody has pooped (two cats, two trays, both using them exclusively as they haven't figured out they can excrete outdoors). When a poo first lands there is a definite smell, but all of the wetness is instantly sucked out of it by the litter and that makes the smell pretty much disappear too.
We also have a special reed diffuser near the tray that is most preferred by both cats, just in case.
And neither tray lives in a room that we are regularly using: one under the stairs behind a curtain, one in the 'cat room' where they are fed but otherwise it's basically a bit of dumping ground/corridor. We haven't got cats shitting in the same room as we cook/eat/relax.
My top tip, other than buying super-clumping litter e.g. World's Best, is to get a much bigger/deeper tray than you think you need and put several inches of litter in. The cats love it and any waste never reaches the bottom so - while I wouldn't want to eat my dinner off it - the tray itself really doesn't require regular cleaning.
World's Best is expensive but we only get through a bag a month with two (mostly indoor) cats.