These processes happen more quickly at higher temperatures. The usually quoted rule of thumb is that chemical reactions double their rate for each temperature increase of 10 Celsius degrees (C°) . As with all rules of thumb, there are many assumptions. This particular one is most applicable to reactions with activation energy values around 50 kJ/mole. Many of these are important at the usual temperatures we encounter. It is often applied in shelf life estimation, sometimes wrongly. There is a widespread impression. for instance in industry, that "triple time" can be simulated in practice by increasing the temperature by 15 C°, e.g. storing a product for one month at 35 °C simulates three months at 20 °C. There is enough variation that this practical rule cannot be relied upon .