apparently having imperfect/fluctuating power to the PSU slowly "erodes"the internal components.
Your source for this bit of "wisdom"?
A good PSU is designed for a relatively wide range of AC input power.
Because the only moving parts in a PSU are one or two fans, there should be nothing to make a clicking sound. If you hear a clicking sound from your PSU, it's because it is a POS.
You cannot have too much load on a breaker. If you tried, it would trip. You can, however, have inadequate wiring in the house.