Some Jews, though not all, tend to write G-d instead of God in situations where the writing might be printed out, in order that the printed writing can be thrown out, for example, without defacing God’s name. The word God really doesn’t fall under this though, because we don’t believe that God is God’s name, or even one of them. It only really applies to names of God and titles in Hebrew. I mainly do it just out of habit, and not thinking to do otherwise. I’ll also add that even those Jews who consider it necessary to abbreviate God won’t go around telling anyone else they’ll be forever damned for not abbreviating it. It’s pretty much just left to private discretion, in other words, between yourself and God, as most issues of belief are left to private discretion.