Resources are limited, which means you can’t do all repairs with the same level of thoroughness. For your least important equipment, you want your repairs to be as efficient as possible. For your critical equipment, you want them to be as effective as possible.
If you have a 400-hp motor driving your plant’s main air compressor, do you just swap it out with a new one if it fails? No. One reason is that is quite an expensive motor to simply stick into the same environment where one like it just failed. However, the main reason is if you lose that compressor much of production must shut down.
So, your repair is quite thorough, including a post-mortem conducted by the motor repair shop. You’re not just going to determine the failure mode and solve for it — you’re going to perform a battery of tests and examinations to look for contributing factors. In this case, you identify some load issues that put excessive strain on the (old) motor. While one crew is replacing the motor, another is repairing those issues.