Non-prescription Contact Lens

[deliverancee]

I'm here again, needing help : D
[ Because you guys are super rad! ]

Non-prescripition contact lens:

1. Do you know how long I can wear them from?
2. How do I know I can't use them anymore?

I got my contacts in December/January and I've only worn them like, once or twice.
I got them for about $20.
I use opti-free replenish.

Thanks a lot ! : D

PS / Sorry if it doesn't make sense. >_<