If spending the last 15 years trying to train my wife is any indication, the biggest mistake people make is carelessly leaving too many totally unneeded things running at once, and failing to clean up after themselves.
The question of what memory you need isn't only answered by "am I running out of memory". It's "what is my behavior like and am I taking care".
I can attest to the simple example that going for 3 weeks refusing to close Chrome tabs will run you out of just about any memory you have.
It's like money, you spend it thoughtfully, except many people don't - they just assume the computer should do 'whatever'.
It would be like never changing the oil in your car, and then finally concluding "I guess modern cars just need more oil"
