This article reviews the end-use factors that can affect the performance of pressure sensitive adhesives. It can be used as a troubleshooting guide when problems occur. It is assumed that the most appropriate adhesive formulation has been chosen for the specific application. The problems described are primarily related to variability (sporadic failures) or to cases when all of a sudden the adhesive does not work anymore. There are a number of possible reasons for problems occurring when using pressure sensitive adhesives (PSAs). The normal reaction is to blame the adhesive - to claim that something has changed in the formulation or end product. In fact (and especially in the case of pressure sensitive adhesives), the problem is caused by factors occurring after the adhesive has been delivered to the end-user. These are usually the result of improper storage, contamination, incorrect application, and so forth.