Obviously, you don't know if, say, an electrician is wiring a new fuseboard correctly or a gas engineering putting a gas fire together properly. But, a lot of the time, you CAN observe what tradesmen are doing, i.e. whether they're fitting the radiator in the right place and level, or whether a gardener is trimming a shrub to the right size/shape, or a decorator is hanging the wallpaper neatly or painting neat edges etc.
As for tidyness, again, depends on the job, but if someone is, say, drilling a hole in a fully furnished room, I'd expect them to put a dustpan under the drill, or if, say, a gas engineer is using spray or lubricant, I'd expect them to put the container on a mat/paper rather than on a brand new cream carpet! In an otherwise empty room, with no furniture, no carpets, etc., then absolutely the tradesman can crack on making as much dust etc as he wants. It's all a matter of context!
We once had a carpet fitter who plonked a can of red bull on our brand new wood fireplace which left a circular stain that was impossible to remove as the liquid was absorbed into the wood.
There's a massive difference between inevitable mess of big messy jobs and sheer sloppiness from lack of care and consideration!