For any given substance, the heat capacity of a body is directly proportional to the amount of substance it contains (measured in terms of mass or moles or volume). Doubling the amount of substance in a body doubles its heat capacity, etc.
Conventional soft contacts can last up to a year; conventional rigid gas permeable (RGP) contact lenses can last even longer. Frequent or planned replacement contact lenses last one to several months. Disposable contacts last from one day (daily wear) to up to two weeks (extended wear).
Here are a few additional tips from the Mayo Clinic to help you practice good contact lens care: 1  Contact lens solution products have expiration dates; keep an eye on the bottle youâre using and discard it once itâs past due. Lens cases shouldnât be used indefinitely either, so replace them every three to six months.