yeah, every couple is soooo different....all depends on how committed and really in love these people are. i, personally, would not live with someone b/4 i was married....that's part of marriage....if you love someone enough to be married, you love them enough without "testing the waters." at some point, the marriage will be strained, so what? you gonna act out every possible scenario to see if it "clicks?" not for me, all i'm saying.
and my parents have been together since they were 14, married in '76....and just bought a brand new mustang convertible...........those crazy, crazy kids!!!