Do you mean you'd like to run additional credit checks and background screenings while they occupy your rental?  

Screening continues until the lease is signed and there is no obligation to offer the lease to someone whose application is accepted that will not conform to your requirements.

@Nelson Del Castillo Cheapest I found Hartford lumberEnergy star windows per your sizes @ $169 each plus tax.Not energy star per your sizes @ $156 each plus tax. 1/2 screen included on both.No delivery charge.

I think it is very important to look beyond the hard data in screening tenants and also look at the soft data - such as, how they act in-person, their tendencies, social media, if their car is clean and things such as that.

@Cris AguiDepending on the type of properties you have, proper screening with 1-yr leases would be best.

Unless there is specific concern, my personal view would be to discuss occupancy during the screening process (it is a good idea to go over the lease at signing as well).

If you do decide to allow them to be added to the lease, make sure you follow all normal screening procedures that you do on the property (credit score, income, etc.).

I take tenant screening very seriously and I closely look at the character of my tenants up front.

@Will RugeleyI am not sure how many properties you like to manage but if it is not a lot, you can totally manage by yourself using property management software or combination of accounting softwares, tenant screening, rent payment software.If you would not like to bother property management aspect of real estate investment, you can always look for property managers in your area.

That usually runs another $1,000 or so.I make each occupant complete a screening so I know there aren't any sex offenders or dangerous people living in the unit.