Should you always log out of your browser, email, Twitch, etc?

Stand up.

If others are using your PC and you are afraid that they would spy on you or do things on your behalf, then yes.

Nope, it's yours.

Okay, there are scripts that try to steal credentials through unknown browser holes, but a good ad blocker like uBlock Origin in conjunction with uMatrix often helps.

If the PC (the user account) is still used by other people, I would do that.

Mfg Jannick (L1nd)

Anyone who is permanently logged in to Google, online shops, Twitter, Facebook, etc., undresses. You draw a data trail behind you that runs counter to data protection.