The signal strength at your location may or may not be strong enough for good reception. Digital TV broadcasts, much like digital cellphones, do not suffer a progressive loss of picture quality. They either look perfect or they're not there. There's very little in between.

This is not to say that a perfect signal is required. The receiver is able to compensate for a certain degree of data loss.

Signal strength decreases with distance and any terrain or buildings between you and the transmitter will have an effect.

Ideally, it would be possible to see the transmitter from some part of your home, or at least from somewhere on your floor, if you live in an apartment. The signal can get through the walls of a wood-frame building but may be blocked very quickly by concrete.

Since there are so many variables it's easier to just go for it unless you are certain that no signal could possibly reach you.