You are not letting the market completely dictate your lot rent rate increases.  

Common sense dictates that you keep 1 month's rent, unless you get it re-rented in time.If you get it rented on say Aug 15th, don't give them back 50% of the rent amount, just keep it for your troubles....

The age of the property and any updating will dictate your maintenance fees.

It would be absurd to Fannie Mae to dictate that you have to go on vacation a certain number of days every year. 

The best and most optimal path forward will essentially be dictated by their wishes, and should take into consideration asset protection, income taxes and estate/gift taxes.

This will help dictate what price home you can afford so that you can let your realtor know what range you should be looking in. 

It isn't their "choice" to use the Security Deposit to pay rent, unless the lease dictates that.

While certainly you do not want an adversarial relationship with a tenant, if you allow them to dictate how you manage your property it may spiral to that relationship and infect your other tenants once they hear they can negotiate rent increases.

Or, use Quickbooks and dictate rental items.Personally, I set up a separate bank because I have a few rentals. 

Let those dictate what u buy.