Threaded inserts work great, better than screwing directly into the wood, because they won't strip like wood and because it is easier to find the hole when putting the pup in (especially P-90s). There are different types available...knurled/press fit or screw-in. I like the screw-in type better, they seem to be more secure and are easier to replace if needed. But if your wood is stripped it is very easy/cheaper just to repair the wood (drill & fill).