I usually add a quick login hook on computers I episodically manage to run a few additional maintenance tasks such as emptying the trash, checking for software and anti-virus updates, etc. thereby maximising the clean-up potential of a reboot.

An oft-underestimated advantage is that it brings the interface back to a default state, too, enabling the user to start again afresh, and often enabling him to find the button or menu that he is, in fact, after.

Rebooting is troubleshooting step number one.