Are you tied down to a contract with Koodo?

I'm trying to decide what phone company to go with. My dad does NOT want to be stuck with the same company or phone for a long time, though. If we end up having any issues with them, he wants to be able to just leave. He's thinking we should go with Wind Mobile but it doesn't seem like they have a huge variety of phones. I know that if you have the koodo tab that you can get rid of the phone whenever you want, but what about the company? Do you still have to stick with them?
Thanks so all answers!!