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).
In short, donât shop for diameter only, but look at the limbal ring design at the same time. Circle lenses have 9-12 months life span once the vial bottle is opened. For daily usage, circle lens can normally last 6 to 8 hours. However, some people do find it tiring/ drying up after few hours.