Sooner or later, the time comes to disassemble the engine for repair, and it is very important after that to measure the wear of the cylinders. Using your fingers or "by eye" to determine the difference in diameter, you will not need the exact tools.
If there is no caliper in the garage, this is not surprising, the device was always expensive and due to the fact that it was rarely used, it was available only from motorists and occasionally from garage masters. At the moment, with AliExpress you can order a caliper for about 3,000 rubles, but the question arises about the accuracy of the testimony and the appropriateness of such a purchase.
When the device is ordered and received it will be good to compare its readings with a certain standard and learn how to use it, because its design is slightly different from the Soviet counterpart. To take into account all the nuances of working with the Chinese caliper, you can watch a video in which the process of measurement and calibration is explained step by step.