With a market that is rapidly increasing in invetory, I've written more lease/options in the past two months than I have in the past two years.  I'm seeing a problem recurring through these.

The lease periods are running for 12-18 months (in one extreme case, 3 years), and the parties are executing a contract with a definitive purchase price at the inception of the lease.  For the listing agent, they would do well to insert a provision after the purchase price that says "or appraised value, whichever is higher".  For a buyer's agent, the converse would hold.  If the contract is not contingent on financing, one of the parties would need to agree in the contract to fund an appraisal within 30 days of the closing date which would be binding on the parties.

I just see scenarios happening 12-18 months from now where sellers are pissed that they are leaving $50,000 on the table because they made a bad deal a year previous, and I know who is going to hear about it... :)