Fully agreed... especially with phillips or standard screwdrivers... using a #2 phillips on a #3 screw will ruin both the screw head and wear out the screwdriver tip in short order if done frequently or if a screw is in nice and tight and ya try to break it loose with the wrong size tip.
Standard screw heads get ruined mainly by using too narrow of a screwdriver tip, especially when trying to break one loose but just about as bad when tying to tighten.
Also, ya definitely want quality screwdrivers even if you can only buy one at a time. I buy a lot of hand tools from harbor freight but all my screwdrivers are craftsman or better since I hadn't seen any of theirs that are good enough quality.. the rest of their hand tools are really nice compared to how they were about 15 years ago. The only exception with the harbor freight screwdrivers is their removable screwdriver tips (also known as apex tips) are good quality.
I probably mentioned it already but if you keep a small tube of valve lapping compound in your tool set, you can dip your phillips tip in the compound for extra grip on overly tight screws, just don't use this trick on internal engine parts or let it get in your engine or carb.
Another very useful tool when dealing with these engines or motorcycles in general is a good impact driver set, these will break loose most screws before they get the chance to strip the heads, and if one is about to strip, the impact driver works great for breaking it loose before it's too late. And if all else fails and one does strip beyond help,an easy out set is another very valuable tool to have...
This is just general info for anyone to read and use, I dunno how bad yours is yet, but hopefully some of this helps....