This is my 1979 MXR Phase 100 that I’ve owned for about fifteen years. During that time, I’ve wrecked its ‘vintage value’ with a true bypass switch, installing a DC power in, cleaning out the gross dusty gunk, and general wear and tear.
Why would I do such things?
Because it’s meant to be played through and used, not to sit in some vault.
If you want to make investments, buy stocks or bonds.
Buy gear, play music.