[ffcmike]

Imagine you were to lose something, for example a pair of keys.
Now imagine you spend a couple of minutes searching for them, then you manage to find them. Would you then continue searching for them after you've found them?
Ofcourse not, that would be absurd.

Checking conditions after a condition has already been established may not have any real effect on performance in this instance, but it makes just as little sense.