Chain inspection is not limited measurement. Although link length measurement is important so is the wear on the plates. The general condition of the chain must be assessed ie no siezed links, bars must be free of cracks, pins must be checked to ensure no rotating has occurred, no rust corrosion should be evident.

Most service manuals have a section on how to check chains.

In Ontario Canada, we have to certify fork lifts as being capable of handling the rated load yearly (a long winded requirement in our OHSA that basically means every 2000 hours). I have helped develop the criertia used for this.