Write the criteria down before you advertise
Written rental criteria are the single highest-leverage document in leasing. They state the income standard, the credit standard, the rental history standard, the occupancy standard, the pet policy and the identification requirements — before anyone has applied, and therefore before you know anything about who is applying.
That sequence is the entire point. A standard written in advance is applied to people. A standard invented after you have met the applicant is applied to a person, and that is where both bad decisions and fair housing exposure come from. Publish the criteria, give them to every enquirer, and apply them the same way every time.
It also saves you money. Applicants who cannot meet a clearly published standard mostly do not apply, which means you are not paying to process applications that were never going to work, and they are not paying an application fee for the same.
What actually predicts payment
Income relative to rent matters, and a ratio is the usual way to express it — but the ratio is a starting filter, not the answer. Stability is what actually predicts the next twelve months: how long the income has been in place, whether it is likely to continue, and whether the household has carried a similar payment before without incident.
Verified rental history is the strongest single signal I know of, and it is the one people skimp on. Speak to the previous landlord, not the current one — the current landlord may want the resident to leave and has an incentive to say pleasant things. Ask specific questions: did they pay on time, did they give proper notice, was the property returned in reasonable condition, would you rent to them again.
On credit: look at the pattern, not the number. A score dented by a medical event three years ago with clean housing payments since is a different risk from the same score built on a recent run of missed obligations. The score compresses a story into a digit and you are entitled to read the story.
Be careful with self-reported documentation. Fabricated pay stubs and fake reference numbers are common enough now that verification against an independent source — not a phone number the applicant supplied — should be routine rather than exceptional.
Fair housing: the exposure is in the small talk
Federal law prohibits discrimination on the basis of race, colour, religion, national origin, sex, familial status and disability. Arizona has its own fair housing provisions, and individual cities may add protections, so check the jurisdiction each property is actually in rather than assuming one rule covers the whole Valley.
The formal decision is rarely where owners get into trouble. The exposure sits in advertising language, in casual remarks during a showing, and in inconsistency. "This is really more of a quiet street" said to one family and not another; "great for a young professional" in a listing; steering an enquirer towards one property and away from another. None of that feels like a decision at the time. All of it is evidence later.
Two rules keep leasing staff safe. Describe the property, never the ideal resident. And if a question is not on the written criteria, it is not a question you need the answer to.
Disability requires a further step: reasonable accommodations and modifications have their own framework, and assistance animals are not pets and are not subject to pet policies or pet fees. That distinction is one of the most frequently mishandled areas in residential leasing. If you take applications, you need to understand it properly.
Adverse action is a procedure, not a phone call
If you decline an applicant, or approve them on different terms, based in whole or in part on information in a consumer report, federal law requires an adverse action notice telling the applicant which consumer reporting agency supplied the report and that they may obtain a copy and dispute it. The agency did not make the decision; you did, and the notice says so.
Handle it in writing, the same way, every time. Keep a record of the decision and the criterion it rested on. An owner who can produce a written standard and a consistent file for every applicant is in a fundamentally different position from one who is reconstructing a decision from memory.
The screening that continues after move-in
Screening is not one gate at the front. The lease should be clear about who is authorised to occupy the property, and additional adult occupants should go through the same application process rather than appearing informally over time. This is not officiousness. If someone is living in the home and is not on the lease, you have no agreement with them, no screening on them, and no straightforward remedy involving them.
The same applies to pets and to subletting arrangements. The point is not to police people's lives; it is that the document has to describe the actual occupancy, because that document is the only thing you can rely on when something goes wrong.