There is a discussion over on theApartment Association email discussion group about income criteria for unmarried co occupants vs. married occupants.
A tenant is a tenant, regardless if they are married, cohabitation, straight, gay, white, black or green.
If you are using a reasonable income criteria for screening, that is good as long as you don’t factor in the other things such as marital status.
Your protection if occupant A departs on month two of a year lease is to let occupant A know you are not releasing them from the obligation they have to you under the rental agreement. Simply moving out does not relieve the vacating tenant from their obligations under the rental agreement.
As soon as you start analyzing if applicant A has enough income without applicant B for unmarried tenants, but consider the income of both undividedly for married tenants you are running afoul of Fair Housing, at least in Wisconsin.
While marital status is not a protected class under Federal Fair Housing, it is a protected class under Wisconsin’s Open Housing Law and in a number of other jurisdictions.
Plain English version:
https://dwd.wisconsin.gov/dwd/publications/erd/pdf/erd_9523_p.pdf
Statute:
https://docs.legis.wisconsin.gov/statutes/statutes/106/III/50/1
106.50 Open housing.
(1) Intent. It is the intent of this section to render unlawful discrimination in housing. It is the declared policy of this state that all persons shall have an equal opportunity for housing regardless of sex, race, color, sexual orientation, disability, religion, national origin, marital status, family status, status as a victim of domestic abuse, sexual assault, or stalking, lawful source of income, age, or ancestry and it is the duty of the political subdivisions to assist in the orderly prevention or removal of all discrimination in housing through the powers granted under ss. 66.0125 and66.1011. The legislature hereby extends the state law governing equal housing opportunities to cover single-family residences that are owner-occupied. The legislature finds that the sale and rental of single-family residences constitute a significant portion of the housing business in this state and should be regulated. This section shall be considered an exercise of the police powers of the state for the protection of the welfare, health, peace, dignity, and human rights of the people of this state.