Sometimes your system just starts slowing down. You may not notice it at first, but then one day it occurs to you that that circle, which is supposed to be a cursor, suspiciously spins a lot longer than it used to. You realize you can't remember the last time you completely shut down and restarted. And you have over 40 tabs open in your browser. And way too many programs/apps going at the same time. And there's stuff working in the background you didn’t even know existed. You're constantly looking for an outlet to plug in and recharge the battery, which doesn't seem to last nearly as long as it used to.
That's when it's time to reset. I'm not talking about a quick CTRL+ALT+DELETE. I'm also not talking about your laptop, tablet or phone.