The lights in your apartment just went out, again. And it’s not your fault, again.

How did this happen? For the first time you had the luxury of choosing whom you live with. You carefully selected a group of people from your friends, relatives, classmates and coworkers. That friend who somehow enjoys vacuuming, the girl in massage therapy school who always needs people to practice on, and the guy who always brings leftovers home from his line-cook job. Heaven, right?

But after the blissful housewarming, a couple of months go by and the dreaded truth comes out: your roommates don’t understand money.

Many of us garner some experience in just how senseless our peers can be during college/university, when we first step into the great and terrible world of shared living space. But now you’re an adult, who pays taxes and votes. Playtime is over, and if your roommates don’t understand this, you must take them to task. You’re sharing bills and rent and maybe groceries, after all. Here are some issues that need to be and stay on the table.

Communication: If don’t have regular house-meetings with your roommates, start them up right away. Holding people to account does not have to be accusatory, but it will often be unpleasant. If your shared finances are disorganized, creating an organized place and time for discussing them will make a huge difference. Get a talking stick, read anonymous suggestions, meditate together, whatever floats your boat. Just make sure that you are specific in your grievances, and have cookies or hard cider on hand to take the edge off when you’re done.

Groceries: Most girls I know between the ages of 18-to-26 do not know how to shop. Some key rules are: Shop to a list; specifically, a list you wrote up with your roommates before hand, taking the weekly flyers into account. Compare prices at every store in reasonable walking distance from your abode, and pick the cheapest one. Buy more than one of a staple item if the sale savings are over a dollar. And most importantly, if you can’t figure out which of two similar items is the better deal, the price label on the shelf has fine print telling you how much you pay per 100 grams.

Extras: If you have a roommate who takes 40 minute showers, or who turns the heat up to 26 degrees and then leaves for the day, you must consider reevaluating your utilities structure. In cases like this, it can be hard to catch the offending party redhanded, and harder still to decide how to even the score monetarily. Do not allow these problems to fester, or they will be fodder for arguments later. It is possible your roommates are just unaware that their complacency is costing you. Bring it to their attention (with examples) (nicely) at the house meeting. Remember the cookies and cider? They’re for now.

WiFi: The great thing about NetFlix is that you can share it with your roommates. The bad part is that four people using it in the same apartment will suck down your monthly 100 GB of data in a week flat. If your roommates do a lot of torrenting, or if one of them is gamer, they need to cough up more for your internet package. Your internet provider will allow you to monitor usage down to the minute, so you can see if it spikes when a certain roommate is at home. Bring it up at the meeting, and try not to sound accusatory. Or agree to pay a bit more to go unlimited.

Emergency Fund: It will increase both trust and an awareness of shared responsibility with your roommates if you set up an emergency fund, provided the contribution amount is equal on all sides. If one of you gets sick and has to leave work for a month, or has their bike gets squashed by a truck, you will all have peace of mind knowing you won’t have to dip into grocery money just to survive.

Rent: Seriously, if there is a real (expanding further than two months) issue with your roommate making rent, review your lease and see what your options are for kicking them out. This can be extremely tense if you live with childhood friends, siblings or a romantic partner, but if they have $18,000 in student debt, and only a part-time job, they need to move back in with mum and dad.

When it comes to shared finances, tough love is really the only way. Talk about these issues before they arise and you can save yourself not only grief, but money.