1) Ensure that the Hardware isn’t Under Strain
There are plenty of freely available tools to monitor your system; things such as CPU or Motherboard temperature for instance are good at telling you if your fans are working and your components are at or near the point of danger. I would recommend Sandra by SiSoftware as a monitoring tool, as it offers plenty of maintenance and benchmarking tools, and the light version is free.
2) Find the Issue and Solve it Yourself
The first and easiest tip would be to try and find out the problem you’re having, likely by reading up on it and repairing it yourself. For instance, it is much cheaper to replace a video/graphics card-fan yourself than paying someone or replacing the entire card. Granted not everyone has the technical knowledge to do this (and sometimes it just isn’t possible) but in most cases it’s easy to do.
3) Keep an Old System for Spares/Repair
Despite the clutter, try not to throw away your old PC or parts as they may come in handy in case of hardware failures. Failures such as DVD readers/writers, floppies or hard-drives are perfectly solvable with parts from an old system; in the case of a hard-drive particularly, it may save the hassle of waiting for repairs especially if you need your PC for work.
4) Consider Warranties or Renewals of Warranties for Expensive Systems
In the case of multi-core systems or well-equipped gaming rigs for instance, it may be better to purchase a warranty or extend the existing one. In the case of a fried CPU, a PCI-E card failure or something wrong with the motherboard, you will likely end-up paying more for new parts/repairs than what is covered by your warranty.
5) Consider a Hardware Maintenance Contract as Insurance
A “Hardware maintenance contract” is just like an insurance policy in case your hardware should fail. The two standard types of contracts available are “On-site” maintenance or “Depot;” “On-site” means that a tech will come to your place of work/home and fix the problem there, whilst “Depot” takes more time as you need to order the part yourself (with expenses covered obviously).
The main advantages of such a contract are seen if you own a business and can’t afford to diagnose your own problems or maintain yourself. In such cases a contract is highly recommended.