There is honestly never a bad time to inspect your sewer line. There certainly are circumstances, however, where you should have a technician perform an inspection. For example, if you are shopping for a new home, then you should have someone inspect the plumbing. Otherwise, you could end up paying for the repair, which can be very costly. Also, if you cannot remember the last time you had someone take a look at your plumbing, then you should move forward with an inspection.