To upgrade a separate power supply?

On the other hand my Brown Electronics Lab BEL 1001 died after a few weeks use! Needs new power supply caps. It too was built in the mid-80's.

Or, how many years since it was last turned on? If it's in frequent use and working correctly, it may not need replacement electrolytic capacitors. 

After how many years should the caps be replaced.?

Look here

and here.

@hilde45 . Thanks. Very helpful.

Thanks to @hilde45  hilde45 I know to just replace them. Thanks also to Paul McGowan of PS Audio for informative clips.