The periodic maintenance intervals (every 6 months?) is an ideal time to do a cursory property inspection. And, you have every right as a property owner to inspect your property, with a courtesy 24-hour notice. Just take a quick look through the property to note how it's being kept, any damage that has occurred, etc. If there is a serious discrepancy, bring it up with the tenant. They have a responsibility to keep your property in decent shape, not letting things like trash pile up, yards going to weeds, that kind of thing. And, if they're trashing your place, you can evict them before the lease is up because of it.
You may remember a month or two ago in Escondido (near San Diego), there was a rental house where the tenant had all this bomb making equipment and chemicals stashed all over the house. And, when the authorities found out, they ordered the house burned to the ground to verify that all of the materials were destroyed. And, the property owner was ultimately responsible. So, not only did they lose the house to the fire, the County of San Diego sent them a bill for $500K for the destruction and cleanup.
Pictures taken of the house in the months before the discovery of the materials showed that the place was completely trashed inside, with all kids of junk and chemicals stored all over the house. A simple periodic inspection would have turned up this activity, and saved the property owner a lot of expense and grief.