Yes, I do use an egg turner. A hen turns eggs in the nest but I don't have the time to be going in and hand turning eggs multiple times a day for weeks at a time.
I take them out of the turner two or three days before they are due to hatch - depends on if I put eggs into the incubator several days in a row.
On rare occasions I have put eggs in every day for about 4 days - trying to get enough eggs to hatch at roughly the same time. In those cases, I stopped the turner on all of them when the first day's eggs were due to be stopped, but the eggs that still needed a few more days of turning got "turned" by hand. I would prop up one side of the egg carton they were in and switch sides that were propped up, a few times a day.
This year I tried a trick from more experienced breeders and put all eggs into cartons and left them there for hatching. I cut apart the cartons into "cells" of 4-6 eggs each, and cut the bottoms out of each individual egg section. Holes in the bottom of each egg compartment allow air to still circulate. When I took the eggs out of the turner, I put them all into the cut up egg cartons - large side up just like in the turner - and that was how they hatched. I found that my chicks actually came out of their shells faster than just laying the eggs in the incubator. I think it's because they have something to kick against because the carton holds the egg still, whereas just laying in the incubator loose, they end up rolling their eggs all over the place trying to get out because they can't get leverage.