This can work in a 'rich' building where a substantial reserve fund exists or can be created if everyone deposits $$ into it. Our taxes are around $275k after STAR and coop credits this year, with a budget of about $850k and $200k in reserves. You try to collect an extra $250 per month per unit in a squeezed middle class neighborhood to save $2750. And with banks paying maybe 1/4 of 1% interest, you're not getting much there.