This strategy is commonly used in mathematical proofs.
So if we're still trying to get into our email account, we might start with one, two, three, four, five, six, seven, eight, and if that doesn't work, we'll change one number at a time.
Two, two, three, four, five, six, seven, eight, then three, two, three, four, five, six, seven, eight, and so on.
This drastically reduces the number of solutions we need to try because it eliminates any unlikely ones right off the bat.
Heuristics don't guarantee a correct solution, but they do simplify complex problems and reduce the total number of solutions that we'll try in order to get to a more manageable number.