In any business, there’s a constant balance between profitability and service. When you have more than one customer, there’s a balance between customer service and price. Nowhere is that more evident than in the decisoin as to when to re-key the locks on your home.

Some states, such as Illinois, have laws that require landlords to re-key the locks between tenants. If they choose not to do this they are legally responsible for subsequent damages due to theft by previous residents. For the landlord, the costs associated with re-keying the lock between tenants are simply part of the cost of doing business; they cannot be charged to the tenant or deducted from the previous tenant’s damage deposit. Yet in Illinois the law applies to 4-plexes and up, and homeowners who rent out single rooms are exempt. But the reason for the law remains sound: there’s been a problem in the past with former tenants coming back to steal current tenants’ belongings.

In Arizona, the landlord must re-key the lock at the tenant’s request, particularly if the tenant has been a victim of domestic violence and is enforcing an order of protection (“restraining order”). There is no exemption for single-room landlords under the Arizona law. Here, the reason for the law is different: there’s been a problem with people who are rightly locked out of a dwelling coming back to do terrible things to the occupants. (If you think that, as a landlord, you’re somehow immune to attack from a tenant’s aggrieved and mentally unstable ex, please reconsider.)

Re-keying a lock can get awkward if you have more than one tenant. When Tenant A moves out and Tenant B remains in a different room, prior to Tenant C’s arrival you would have to re-key and give Tenant B a new key to the house. The re-keying requirement pertains only to the exterior doors: if you provide lockable bedroom doors every tenant’s key should be different. I never re-key the locks of individual bedrooms because if the exterior door locks are re-keyed there’s no point.

Re-keying can be expensive. If a tenant is re-keying due to a fear of domestic violence, should he or she be required to supply a key to all the other residents of the house? Or should the expense be borne by the landlord? Is it fair to the other tenants to ask them to buy a key every time one of their fellow tenants has drama with an ex?

The only time I charge a tenant to re-key a lock is when he or she leaves on bad terms and/or does not return the key. In such cases, I bill the tenant by deducting the cost of the re-keying from his or her damage deposit. The other tenant (if there is one) generally appreciates my reason for re-keying. I’ve never had a problem with a tenant not wanting to take a new key from me. Of course since that key is free (to the tenant) I wouldn’t expect objections anyway.

Fortunately, I’ve never had to re-key for domestic violence. The kind of tenant who seeks out the kind of lodging I have to offer generally isn’t of the serial monogamist type. My tenants are generally divorced, widows or widowers, or happily married people who want to live cheaply while in town for several months due to work. Such individuals seldom need to flee domestic violence.

Every time you re-key the locks, you should come up with a new combination for your security system or garage door opener, if it can be opened from the outside.