As far as drugs, I would deal with it in a non-curable breach of contract section such as: Non-Curable Breach of Agreement: Any of the following events will be deemed a non-curable breach of this Lease; (a) Police raid upon your Premises; (b) Your arrest for possession/sale/storage of any narcotic/controlled substance/chemical or herbal contraband in or about the Premises; (c) Failure topermit Owner's entry to the Premises following receipt of adequate notice; (d) Failure to cooperate with Owner or any pest controller/fumigator/exterminator following receipt of notice of such services; (e) Defaults by you causing Owner to serve more than two notices to pay or quit, in any twelve (12) month period; (f) A misrepresentation on your Rental Application; (g) Delivery of any security door/gate key to anyone not party to this Lease.

I was extremely close to closing on a property a few months ago but we found a foundation failure that would require a $30,000 fix (jacking up the building and re-pouring).  

All of which we did finalize ourselves.Now the Bldg Inspector has a Subpoena out for him regarding failure to complete for the June 1st OP.

If, in Landlord’s opinion, the pet(s) has injured or disturbed others, or has damaged property, Tenant must permanently remove the pet(s) within fifteen (15) days (or sooner in the case of an emergency) of receiving written notice, and failure to do so shall constitute a violation of the Lease Agreement, and may subject Tenant to eviction.

Failure is not an event.

@Dawn Anastasi good question.Debit cards check for available funds immediately and return a failure instantly if there are insufficient funds.

Failure is not an event.

Failure to vacate by X day and X time shall result in holdover rent being owed as well as an action for eviction being filed against the tenants. 

Failure.

This is setting yourself up for failure the minute one of your properties goes vacant for any amount of time.