so obviously, you shouldn't use pedal where it is not indicated
In addition to what mjames said, skilled pianists will modify pedal application according to the instrument and acoustics of the performance space.
Lol of these are good and valid answers and so I'd like to chip in and clarify a couple of misconceptions.Firstly, the damper pedal, as it's correctly called is most commonly used to make notes sound connected when they are not physically connected. While this is the most common use there are two important points that must be considered when identifying when it is appropriate to use this pedal.
The pedal is the soul of the piano. Unless specifically indicated, it is always used in some way. Do not OVERUSE IT (liek me ) and blur everything (like me ) though, unless it specifically says to do so (20th century stuff where you blend harmonies for a bit)
So how can one really make a legato sound without blurring all the notes together? And especially if you are trying to connect a single voice over several voices and the pedal ends up blurring the whole peice? I think i have all of juicebox's problems...