sadly few things bought today will last 20 years.
I have a solution for that . . .buy things that are 20 years old already, if they've been kept and/or survived well that long already they're probably worth having and where good quality to start with.
I'm specifically thinking guitars and vehicles
a good example is a 1967 Gibson semi acoustic bass, 1994 cost me £700 which was a lot, currently worth approx 1200-1800, new ones which are crap by comparisson are £1200.
likewise old houses tend to be worth more than new ones, because they're well made!