Know when it's time to fix that old piece of equipment or replace it with a high-end system.
Threw my Timex watch in the trash the other day. Kept accurate time for as long as it worked, but failed to keep on ticking beyond the couple of years I owned it.
Maybe it wasn't even broken. Maybe it just needed a new battery. But I'd feel foolish taking a $35 watch into a jewelry store asking to change the battery. That probably would cost about as much as a new watch. Plus, I didn't feel like sitting through a jeweler's pitch for something more expensive.