When working on home improvement/repair projects, I’ve occasionally needed to drill pilot holes into wood that was hard, brittle (e.g. particle board) or sometimes both.
This guide has been invaluable for figuring out which size bit to use.
https://www.boltdepot.com/fastener-information/Wood-Screws/Wood-Screw-Pilot-Hole-Size.aspx
Bookmarked so I can find it again.