Landlords can avoid costly mistakes by heeding these eight words of wisdom:

1. Know thy tenant. Screen potential tenants with a rental application and credit check.
2. Always use written leases. An oral agreement isn't worth the paper it's printed on!
3. A picture is worth a thousand words. Use move-in/move-out checklists supported by before-and-after photographs and videotapes of the apartment.
4. No money--no keys. Do not give the apartment keys to the tenant until the first month's rent and security deposit are paid.
5. Get the lead out. Warn tenants of the dangers of lead paint and abate any existing lead paint.
6. Don't delay until tomorrow what you can do today. Don't wait too long to evict a delinquent tenant.
7. You get what you pay for. Never have tenants do repair work or painting in exchange for the payment of rent.
8. Ignorance of the law is no excuse. Do not ignore building code violations and drug-dealing tenants.