1. If you leave over the objection of the other spouse (i.e. without some way to prove, months later, that you left with the spouse's consent), then you might never be able to get alimony. If alimony is not something you want, then you have nothing to worry about as far as "desertion" is concerned (but see #2 and #5).

2. Or almost nothing. "Fault" such as desertion or adultery can be taken into acount by the judge as one of the many factors determining the proper percentage division (70-30, 60-40, 50-50, etc.) of the marital property.

3. Moving out will start the time running toward eligibility for a no-fault (statutory separation) divorce on the grounds of "living apart." It will not start until then.

4. It should happen before before you sign a separation agreement. An agreement stating that you intend to separate later is no good. A separation agreement signed by two people who are actually living together is probably going to be no good. If you sign the separation agreement and then resume cohabitation, you will probably have destroyed the separation agreement.

5. If a custody dispute is likely to be involved, then the parent who leaves the home is gravely jeopardizing his or her chances to get custody.