I have a very old weed trimmer. It's a Stihl FS 74, and it hasn't been manufactured in a long time. I heard it didn't meet the California emission standards, so it bit the dust. Personally, I think sales dropped off tremendously over time due to how good of a trimmer it is. Mine was purchased in the early nineties, and has been my weed trimmer since.
Over time, I've had to do change some things, including the plug and the carburetor, but those I considered minor problems. One thing I did before, and hadn't for a long time, required me to step back, think about it, and take action.
The last time I used it, the engine wouldn't rev up. I thought about it, thought about it some more, and my thoughts turned to the exhaust. Years ago, I pulled the spark arrestor screen, and cleaned it up. It wasn't clogged, but it was dirty. I decided to take a look.
The screen was clogged. Not just a little clogged; completely covered with baked on carbon that wouldn't come off with brake cleaner. It took a wire brush, a lot of elbow grease, and some time to remove all the carbon, but it finally was without any clogging debris.
I started it, pulled the throttle, and it was like brand new. Now, after the sun is much lower, the air cools, and I get off my butt, I'll go trim what needs to be trimmed.
It's the little things that stop progress, and I'm glad I've been blessed with solving some of these problems.