The first contracts you get from the record-keeping society as well as the "explore [Planet/Moon]" contracts are not repeatable, but all other contracts are randomly-generated. Those contract types which don't have very specific requirements feel kind of repetitive. Especially the "retrieve science from Kerbin orbit" contract seems to repeat indefinitely - only the name of the client seems to change.
But you do not have to accept any contracts you don't like. You can decline any unaccepted contract
without a penalty, although there is a small prestige penalty for this since version 1.1. Most contracts will then get immediately replaced with a similar one. When you ignore new contracts, they will expire after a few days and also get replaced, in that case without a prestige penalty.