Suppose, on return, your clients substituted a barely functioning tool of the same model for one they rented. How would you know?

Are we talking hammers here? :)


We are talking hammers, at my company. So "barely functioning" is no different than "functioning". Components of the toolkits (like hammers, shovels, etc.) get damaged and lost all the time, and that gets noticed and dealt with by humans at the time of restock. The cost of numbering would far exceed any benefit, since the toolkits often get moved from site to site "on the fly", without time to come back to base camp.