The line between domestic bliss and hell is dangerously thin — especially when you’re sharing a bathroom. That’s why the decision to live together should not be taken lightly. “It should feel like a no-brainer,” says Peter Scott, author of There’s a Spouse in My House. So before you make the move, ask yourself: Is this really a smart thing to do? Here are a few tips to help you decide.

* She’s “the one”
“If you believe your relationship is built to last, I like the idea of moving in together before you pop the question,” says Scott, “just to make sure that you guys cohabitate well.”

* You’re halfway there
Some couples never consciously move in together, they just gradually merge their lives and their stuff. If you’re already sharing your space, moving in together may be the right step.

* You agree on the rules
Think of it as a prenup for dating: You buy the couch, she signs the lease. That way, if things don’t work out, you can walk away easily with your pride — and your stuff.

* You think it will improve your relationship
Wrong! Living together will only exacerbate your problems.

* You’re running low on cash
“Pooling funds may sound tempting, but do you really want to be the guy who says, ‘Well, we’re not really in love, but I totally saved like $70 this week! How cool Is that?” says Scott.

* You’re buying time
Living together seems like a great compromise when she wants a ring. But according to Scott, the worst thing you can do is move in together in an attempt to hold her over.