Ok men, time for me to jump in here.
Experience: 35 years in the automotive industry, half of that time I was hands on, the other half, management and then ownership of franchises including: Mercedes Benz, BMW, Volvo, BMW motorcycles, Porsche, Land Rover and Jag, ect...many, many screws and bolts removed and installed in my lifetime.
Change the screws, for all the reasons mention. It is not hard, really. Even if you have to take them out one at a time, change them.
I take off my grips almost every time I go to the range. I change my screws from time to time as constant tightening can stress the threads. Cheep insureance.
Just my 2 cents.