In life, things are rarely black & white. Most of life is spent in a gray area where you are on a spectrum from ‘shouldn’t do’ to ‘should do’. You need to be comfortable living in this range and the uncertainty that comes with making decisions with imperfect information and changing circumstances.
Except for these 5 items.
Definitely never buy these things.
They are all either way too expensive, low value add, or a regrettable purchase.