Mouse and keyboard acting weird/inconsistently

About a year ago, I had a mouse that started double clicking occasionally. Ignored it for a long time, despite it continuously doing it. Fairly close to that same time period, my keyboard also began to occasionally double key press. I've set my keyboard settings so that it shouldn't register same key presses happening in too quick succession, and that mostly solves the issue with the keyboard (though it'll still double key press from time to time).
Recently, I switched back to an older mouse I still had lying around. This one never had double click issues before I replaced it with my newer one, but I'm experiencing double clicks on this one now too. Sometimes, it'll also register left clicks as right clicks. It generally occurs in periods of time. Like sometimes, I can go days or weeks without much issues, while other days it'll double click or right click like crazy all the time.
In the 20+ years I've been working with PC's, this last year has given me more mouse+keyboard issues than all other years put together. Any suggestions?

Summary:
-Got 2 mouses that constantly go through periods of double clicking.
-Mouse sometimes goes through periods of registering left clicks as right clicks.
-Keyboard frequently double key presses.

Windows 10, Version 1903 (OS Build 18362.592)

You have to be sure it is actually double keying not freezing for a while after first click then waiting until next click to register two , in that case you might have what is called "input lag" which usually mean you have a faulty driver of some sort installed and it might called symptoms similar to human hiccups .

now if its double keying for sure its dead , yes this is how keyboards and mice come to their end of life , they just dont go dead , they just start acting bizercal .

Malwarebytes might get you comfy its not a malware pre buying new .

nIGHTmAYOR said:

You have to be sure it is actually double keying not freezing for a while after first click then waiting until next click to register two , in that case you might have what is called "input lag" which usually mean you have a faulty driver of some sort installed and it might called symptoms similar to human hiccups .

now if its double keying for sure its dead , yes this is how keyboards and mice come to their end of life , they just dont go dead , they just start acting bizercal .

Malwarebytes might get you comfy its not a malware pre buying new .

How do I know if it's caused by a faulty driver?

Milennin said:

How do I know if it's caused by a faulty driver?

If you suspect that what you have is input lag then the faulty driver might not actually be the one for them but might be any other device old faulty driver probably not intended for windows 10 , if you do not know specifically which one is that you may have to use a driver updating package (EX : IOBit Driver Booster) , they usually have driver updates for everything even when the manufacturer don't .

But if you suspect its just the mouse/keyboard being assigned faulty drivers then not unless they are from a reputable manufacturer hence you may find several versions of the driver to downgrade or upgrade to on their website to test and see if they resolve this (and those are rare honestly) , the only other options are to test them on Windows PE where they will run with basic generic driver (Link) or to test them on a different PC .

Good Luck!

I don't think the problems are software related.
Old mouses can begin double clicking as consequence of contacts oxidation or weak coil.
Membrane keyboard can also have double key as consequence of membrane failing to act as a coil.

Try a new mouse and keyboard.