The Songwriter's Guild Publishing Contract, considered the most complete in the industry contains a one year reversion clause and I think it gives the option for a 6 month extention for something like a $250.00 advance.

I passed on a Publishing Contract that didn't contain one and the Publisher refused to include it. If someone doesn't include a reversion clause, ask for it to be included. One to three years is plenty. They can always offer a new contract at the end of the first one if they still want to work with the song. If a publisher has something about to happen very late in the contract they can ask for an extention.

Ray E. Strode