Things to consider in replacing a PSU:
a. Is your PSU not working or does'nt perform efficiently?
b. Have you upgraded or added any other HW that will not suffice current power output?
c. Make sure when buying a PSU has the same(assuming same HW specs) or higher power output.
d. Consider PSU mounting on CPU casing with different designs(compact).
e. PSU with good ventilation design for PSU fans.
f. Power pin connectors availability are design with current or new HW specs.
