one night i randomly started getting hardware issues. i had spilled something on my keyboard and mouse (very small, in only a few small places, the spill wasnt even a liquid), within a few minutes the keyboard and mouse started acting strange, i assumed it was the spill, and i replaced both, the keyboard problems stopped but the mouse problems continued.

mouse problems:
- mouse doubleclicks sometimes when singleclicked.
- holding a click cuts in and out.
- problems persist thru hard power resets.
- problems come in "waves", the problems start becoming more prevalent, then go away for a short time, then come back again, repeat.

i think it could be any of these:
- both mice are bad.
- usb port is going bad.
- software glitch.
- something else...

os: linux mint 20.3 cinnamon

kernel: 5.4.0-91-generic

cinnamon version: 5.2.7

If the mice are wireless mice you may have dying batteries in the mice.

If the mice are wireless mice you may have something which impedes the signal sitting between the mouse and the USB transceiver.

You could have dirty contacts. Open the mice and polish or gently file the contacts.

+1 for batteries

wired mice, i never use wireless peripherals

So you 'randomly' got issues....after you spilled something on your hardware?? That's not random, that's simple cause and effect. Think about what you did; you introduced a liquid onto something that was getting power. While it may not have shorted out the USB port/hub totally, it certainly MIGHT have made it flaky. If you plugged the new mouse into the same port and got the same results, that tells you something, doesn't it?

Try different USB ports (front of machine vs. back) or get a decent powered USB Hub, and plug it into a known good USB port. Nothing Linux related about your issues.

it was not a liquid.
that attitude is not needed.
i find it dubious that such a small amount of food couldve caused the usb port to 'burn up' like that.
ill try a diff usb port.

plugged the same old mouse into the back where it was and its not dropping at all anymore

i opened the mouse up and cleaned out some junk, not sure how the small amount of junk inside couldve caused such a problem but its behaving now.

scrolling has always been inconsistent tho, not related to this (its been like that for a long time before even this year), could the contacts in the rotary wheel be worn out?

wow! its not even doubleclicking-on-singleclick(ing) anymore, case mustve been bouncing off the microswitch because of the small amount of dirt

Well, he says spilled something that is not liquid.
Did he spill something solid, granular, like sand?

Is this a desktop? Is it an external mouse and keyboard?
Did he just try another keyboard and mouse? These things are cheap. I have a bunch of them at home. Some come from the trash that other people live out.
My local thrift store sells plenty of them for 3 to 5$.

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Not sure what 'attitude' you are complaining about; you said you spilled something and then had problems....that is not 'random'. And when you say you 'spilled something', what do you think people will assume?? What was this 'food' that was somehow like dirt, yet small enough to get into the tiny cracks in your mouse to such an extent it caused a problem?? Must have REALLY been messy, since it also caused a problem with ANOTHER mouse, right????

And yes, USB ports are fairly sensitive, and small voltage drops/spikes can EASILY cause a port to go flaky. Since you find it 'dubious', you can go do your own research about it.