I'd honestly check them every I clean a gun. I remove all grips no matter what they are made of every time I clean. I like to clean underneath the grips, put a very light coat of oil on the spring and grip frame, and do not like getting gun oil and gun solvent all over Walnut grips. It's one little screw - no big deal and the grips stay in much better condition as well. They do not get dinged, scratched or nicked up while cleaning is being done. This has worked just fine for me for just under 50 years.