I'm always wary if these guides. If you know what you're doing then yes, replacing a capacitor is a quick fix to give your hardware a new lease on life, but you can get seriously injured or even killed if you mishandled the open power supplies these devices often contain.

This guide addresses the danger by saying you need to "wait for a while" without telling you what "a while" is (a minute? 5? an hour?) and how to spot the dangerous parts of the circuit board.

Having said all that, I think a general education on how devices like these can be fixed (safely!) is something a lot educational facilities should offer. Repairing basic and often even more advanced electronics requires little more than replacement parts, a soldering iron and some practice, but people are quick to throw something out when it stops working. The assumption seems to be that things are too complex to repair these days, but in all likelihood dead devices just had some protective circuitry do its job and fail before frying the mail circuits.