Monthly lenses need to be changed every month. Daily lenses, obviously every day :)

It depends on the wearing schedule of your particular contact lens. You should visit your eye care professional, so that he/she can properly assess which contact lens type and wearing schedule would be be suited for your visual needs.

Disposables are one user and throw. Non disposables are up to one year. Semi-permeable lenses can last for years, but need to be cleaned daily and removed from the eyes at night.

Contact lenses are sold as dailies, monthly, biweekly and those are just soft lenses. You should ask the provider dispensing contact lenses to you what kind you have and how often to change them.

Frank Cao