There are a number of common stresses which are used to
* pH (acid/base)
Chemical processes are often catalysed by the presence of acids and bases.  The exposure of materials to these can therefore accelerate degradation reactions.
* Temperature
In accordance to arrhenius kinetics, increasing temperature increases the rate of any degradation process.  Temperature is often used in conjunction with other stresses to increase reaction rates.
* Oxidation 
* Concentration 
* Light