Just like the kitchen, the bathroom is a part of the home you should seriously consider renovating before selling in NYC. It is one of the rare renovations where you just might be able to recoup your expense by selling for a higher price.
If you have old or otherwise unattractive tiles on your bathroom floor, you could consider laying new, sleek, modern tiles on top of them versus digging out the old ones. Similarly, if you have older bathroom wall tiles, you could consider glazing them over rather than ripping them out and replacing them. Sometimes, a simple deep scrubbing and cleaning session will do the trick.