Guess what...

20.000 hours is two years continiously. That is much too much.

Lots of normal household equipment which is always 'on' will fail after some years, simply because the rectifier caps get bad.

For instance an 85°C type, actually used at 85°C it is only 6000 hours. (Data: Vishay capacitors)

At lower temperature lifetime increases a lot. At higher ripple current, lifetime decreases. Try to find these informationw in the data sheet of your capacitors.

Consider Mundorf Tube-Caps. These are foil caps, with the size of electrolytic caps. Oh yes, it excists :) Just these have a few uA leakage, but for power supply that is no issue. They last for ever.