Landlords - Follow the provisions of your lease to the letter!
On top of that, if you do not follow the letter of the lease
, you may be opening yourself up to exposure down the line in the eviction process. Plus, when you do what you set down as policy, it is out of your hands. There are no stories allowed, if you are lenient one day then strict the next; your tenants will let you know that you are a bad landlord. If you consistently do what you say, then you may not be considered nice and/or understanding, but they can't ever say you were not fair. Being fair and consistent every day is the trademark of a successful business and will eliminate a great deal of stress down the road.
Landlords - Follow the provisions of your lease to the letter!