How many coats of flooring polyurethane should I use on my hardwood floors?

The number of coats of flooring polyurethane that you apply is a matter of personal preference and your budget. If you only have enough for 2 coats, then you can only apply 2 coats, but if you can swing it, there's no reason not to apply a third. As a rule, though, 3 coats should be plenty as the more you apply, the more you will have to remove if and when you want to refinish your floors. Optimally, you should use 2 coats: the first to seal the floor and the second to provide a shiny buff coat.