Mine is around 6-7 years old. Started off as an Antergos on T450s, then moved to T480 and later on I replaced the extra repos and the startup logo with EndeavourOS after the Antergos ones went dark.
However, I can see a noticable slowdown and some services occasionally acting weird - once every few months i need to switch to a terminal and use loginctl to unlock my session. I am seriously considering a reinstall, no matter how humiliating that sounds.
I tried to do a reinstall a while back. Gave up around 4 hours in. Installing arch was easy, getting it how I liked it on the other hand. That was gonna take another couple weekends of figuring out what I did 5 years ago to make X work just right.
I did a re-install last year to get rid of the clutter. I created a document that describes every step. Whenever I install a new package, that is going to be useful, I add it to pacman -S command in the document.
I expect the same, but on the other hand many things related to X configuration have improved since then (dpi, multi-screen, etc), so I was hoping the result would be better. I need only xfce, appmenu and plank anyway.
However, I can see a noticable slowdown and some services occasionally acting weird - once every few months i need to switch to a terminal and use loginctl to unlock my session. I am seriously considering a reinstall, no matter how humiliating that sounds.