How to live together (without killing each other)
Here’s the thing: Sharing a space is tough, especially if you’re accustomed to living alone. And sharing a space with someone from the opposite sex? Way different than splitting a converted one-bedroom apartment with a roommate to save on rent. It’s one thing to have a roommate borrow your clothes and return them stained and wrinkled (you can ditch her if you get sick of it) — but that guy that accidentally always leaves the toilet seat up? He’s not just going to move out because you’re sick of falling into the toilet in the middle of the night. So it’s good to know how to work out these little squabbles before you actually get married (you’ll have much tougher issues down the line, believe us).
Each other’s financial status
From divvying up the rent to fighting over the cost of cable, learning how to share expenses early on will make it easier to deal with the bigger ones that come up once you’re married — mortgages, college tuition, caring for an elderly parent. While you may get a tax break for being an official Mr. and Mrs., you won’t get a break on your student debts. It’s important to know the state of each other’s finances — the good, the bad and the ugly — before you marry into a mountain of debt.