A good way to keep an eye on your fender bolts is to put a very small dab of white (or any other color) paint on the side of the bolt head. Take a look once in a while and if that paint is still in the same place, then you know the bolt hasn't loosened any. Obviously, if the painted dab is in a different location then your bolt has begun to loosen. Then I think I'd get the wheel off and the bolts tightened.
2010 Thunderbird SE