Normally your renters agreement will have a clause saying that they can only increase the rent by X% a year. If they want to go above X then they need to give you one years notice. At least my rental agreements have looked like that.
In my experience, leases are exactly the opposite. You sign a lease for up to a year and are locked in at a certain price over that year and they do whatever the hell they want to when it comes time to renew your lease for the following year. Your option would be to switch from annual lease to monthly, but you're often looking at paying double the monthly rent, then.
Yeah my option is an annual lease, they can only change the rent @ the end of the lease (that's why the minimum when they go above the max is 1 year - basically you always have @ least a year at a predictable rate).