Most S&P 500 declines have been short in duration. 

Finding a new tenant who doesn't pay on time or doesn't take care of your property.Have have it good right now and don't realize it.I would approach them with:You guys have been great tenants and if your willing to sign another 1 year or 2 year lease I will hold your rent amount at these levels for the duration of the lease you sign.Then I would thank my lucky stars if they sign a new lease at same rate.Take care of your great tenants.

Its longest duration was 8 years. 

During that time, I offered to waive rent for the duration until AC was fixed or pay hotel until it is fixed. 

Also, I'm hoping that sending this questionnaire would keep the tenant in the property for a longer duration. 

Also look into duration limits for residential leases. 

If they expect you to provide the 60-day notice then they should honor their 30-day clause; both are typical duration but theirs could be different.

For instance, towns that are mainly Republican cowboy types, or only have one real employer and whether or not it's likely for that employer to stay the duration, or can you handle renting to pot heads in the pot growing areas and deal with potentially really high water bills - you just really need to know and understand the affordable areas and the culture and job market or if it's realistic to expect to rent long-term to retirees, what's the healthcare situation, etc., etc., etc.Now, if you do your homework, and spend hours and hours of time researching and traveling there to get a feel and understand them, and you have the ability to really converse with people who may not be the class you're used to, etc., or maybe they don't speak English very well or at all - then you can probably find that you can make a profit.But, anyone who goes into this business expecting to get rich quick without having to do any work is probably going to fail anyway. 

Look over the language you have in your lease for duration of "guests".

They wanted to know the duration of my stay and my email address.