Your contacts will typically arrive in a saline solution. Unopened, they can stay in that solution until they reach their expiration date. But that doesn't mean that contact lenses can stay in other types of sterilized fluid indefinitely.
Contacts should not be left in multipurpose, disinfecting, or hydrogen peroxide solution for more than a day or two. After a few days, the ability to disinfect has been compromised and the lens structure may have started to dissolve, too.