I am replacing several light [dimmer] switches - not moving location of switches. My current back boxes are only 16mm deep, for which there is very limited product availability.
Several attractive replacement dimmer switches require minimum 25mm or even 35mm back boxes.
So I have two options - to simply replace the current switches with ones compatible with 16mm back box, or a two-stage effort to first replace the back boxes (say with 25mm) then install new light switches that require 25mm back box.
My question, on which guidance would be very welcome, is...how difficult is it to replace back boxes? And are there any other related tricks or advice.