Don't worry about it if it's working fine. Your PC uses only around 200W while gaming, possibly 250W in particularly CPU heavy situations - not even half of your PSU's rated capacity. Capacitors age fast if you push them too hard, but in your case, the unit is probably going to easily outlive its 5 year warranty.
I'm not sure which review you read, but according to JonnyGuru's review, the primary caps are Japanese Nippon Chemi-Con (basically, the best you can get), while the seconary caps are Teapos which are average quality, decent enough for a low wattage rig like yours.
Pop the PS case open and look at the capacitors on the circuit board.I have a 3 year old Cooler Master Silent Pro M600.
I read a review about the capacitors lasting just 2 years.
Should I be concerned?
Is it going to start having problems soon?
Pop the PS case open and look at the capacitors on the circuit board.
If you see leaking or bulging capacitors, start PS shopping.
Yes, do it...
No reason to settle on some refurb replacement.
If the PS goes out, it could take other components with it. Cooler Master doesn't cover parts damaged by their PS going bad, do they?
Even the no-brand PSUs used for budget builds rated at 300W and stuff last many many years. You have absolutely no reason to be worried.