I have been certified for 12 yrs and have only used my drill to start taking down product. When you get closer to natural nail bed you use a hand file and nothing overly course. I use 2-3 different files while approaching a natural nail bed.Electric drills shouldn't be used on the natural nail!! My past lecturers at NSI couldn't express this enough and it is known to cause all sorts of problems!
When getting extensions the nail should be lightly etched using a normal nail file to remove surface shine and create a rough surface for the acrylic or gel to cling to.
An electric drill is completely unnecessary for this part of the service and to be honest I think it is just lazy!
The only time a drill should should be used(if ever) is once the acrylic/gel is applied to speed up the filing time as it can take ages.
Also if a nail tech pulls out a drill, make sure they have a certificate on the wall or with them that says they have done a course and are qualified to use a drill.
Better to be safe than sorry!
Hope this helped xx