The older one is when taking subsidies the closer they need to pay attention to this. If your in your late 50's or older, the pay backs can be quite large if you go over 400% FPL on income. Such examples might be a large year end mutual fund distribution or maybe you inherit an IRA and take too big of taxable distribution without realizing it is income. A mistake at that age could lead to a high 4 figure or low 5 figure subsidy payback..
That would suck. Personally, I wouldn't accept a government subsidy under any circumstances, because I don't believe in free lunch's. Once you take it they got you.
I won't be happy until we have a true market driven health care system, where price is determined by the interaction of supply and demand.