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).
Most contact lens wearers today are nearsighted and choose disposable soft contact lenses. If you wear disposable contacts daily and discard and replace them every two weeks â the most common lens replacement schedule recommended by eye doctors â you can expect to pay roughly $220 to $260 for a year's supply of lenses and another $150 to $200 on contact lens solutions, for a total annual cost of roughly $370 to $460 to wear contact lenses.