I have lots of batteries for these games that I bought in bulk. I already re-did all my own games and the rest of my batteries will go stale by the time I need to replace them again. I’ll bring all the equipment needed for replacement, and will do it, for you, for free!
I can even preserve the existing game data if it hasn’t yet been lost. (Not an absolute guarantee that I’ll succeed, but I haven’t lost one yet).
So, bring along your games even if you don’t plan to play them!