Here in Europe the course is different. First the masons do whatever they want and then the electricians channel for their conduit and boxes. After the conduit boxes, plumbing ect. is in place the plasterers come and finish the job. I still haven'T managed to figure out how the pros figure out how deep to set the boxes since that widely depends on the plaster thickness. Probably they don't think about it at all, all new construction I've seen has the boxes recessed about 3/8" into the walls, extension rings are unknown here. Probably the sparkies rather set the boxes much too deep than have them protrude from the plaster. Old work usually involves the electrician doing all the plaster patching. (tear up walls for cable/conduit + boxes, fasten them with globs of gypsum, pull wires and then patch up the plaster).
