Some people take marriage vows more seriously than others, but by now we should all be aware of the possibility that a marriage will fail. Prenuptial agreements are made in preparation of this possibility, and help allocate property and monetary assets in the event of a divorce. If you’re the type that considers marriage vows to be sacred–to love in sickness and in health–then the possibility of failure can make a prenup request into an egregious insult. It doesn’t need to be that way. That said, these are some of the things you can and can’t manage with a prenuptial agreement.

One of the biggest reasons you might draft a prenup is in the interest of protecting a family heirloom. If you have property that’s been in the family for generations, you’ll want to keep it safe. A prenup can be used to do so.

Estate law gets more complicated after marriage, and you might choose to draw up a prenup in order to keep previously arranged estate plans in place should the marriage fail. This guarantees that assets already owned will still make their way to the intended beneficiaries instead of taken by a spouse during a divorce. In the same way, a prenup can signify what children might inherit in the event of a divorce.

Prenuptial agreements aren’t all about determining what assets return to your ownership during a divorce. They can also be used to outline responsibilities to be carried out by each spouse. They can help determine who is to manage expenses and joint bank accounts, who manages tax returns, who manages investments, how much must be contributed to savings, how property will be distributed in the event of a spouse’s death, etc. The options are endless. That said, don’t expect to decide who stays at home with the children or who washes the dishes and mows the lawn. These are largely financial arrangements, and do not govern personal matters at home.

One thing you can’t do with a prenup is determine alimony in the event of a divorce. Even if this is legal in your state, most judges will strike down the provision or limit what you hope to achieve with such a stipulation.

Prenups aren’t always devised in order to make sure original assets go back to their original owners. Sometimes they prepare for divorce by providing an even distribution of assets in order to spare both partners from the usual stress of a divorce. Such provisions must be handled carefully, however, because judges do read these documents in order to ensure that uneven distribution doesn’t encourage divorce in any way. For example, if a previously poor partner would get an enormous sum of money in the event of a divorce, the provision will likely be struck down.