Investing $10k a year at 6% (average stock market returns are 6-8%) gives you $368k after 20 years (net increase of $297k over inflation at 2%). Even if you jus

Investing $10k a year at 6% (average stock market returns are 6-8%) gives you $368k after 20 years (net increase of $297k over inflation at 2%). Even if you just saved it for ten years that's $100k. Neither are enough to retire on, but it gives you a lot more options. Even if housing increases faster than the stock market, that $10k is $800/month which could be going towards a mortgage (in addition to the rent they are already paying).