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).
The easiest way to stay on schedule with your reusable contact lens care is to follow these tips: 1  Replace your reusable lenses on the same day of the week. 2  Use our free ACUMINDERÂ® service to help you remember when to change your lenses, buy new lenses and when you are due for an eye test.