When paper undergoes repeated folding, the fibres strain initially. Gradually fiber-fiber bonding starts loosening resulting into decrease of tensile strength. Consequently, folding endurance is determination of modified tensile strength. For example the paper failing after experiencing 1000 double folds, in comparision to the other failing after 100 double folds, will not have 10 times more life than weaker paper against folding / unfolding stress while in use but roughly only 1.5 times life. Thus number of folds represented log to the base 10(Log 10) gives better comparision of folding strength.