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).
As I just got back from the optometrist on Friday, lemme share with you my story... I've worn contacts now for a little over ten years, and for all that time, I've been pushing the limits of how long disposable contacts can last. I'm now reaping what I have sown. I have three eye problems, all of which are a result of wearing disposable contacts long past their prime: