how many days can you set timer for? 1 week? 2 weeks? unlimited? bought one then saw its only good for 7 days

You can set the timer to run however often you would like. I think you are referring to the "every 7 days" option that would run the timer once a week. But you can also set it to run more frequently. For more programming information please contact our Orbit support team by phone at (800) 488-6156 or online at support.orbitonline.com.