That depends on the usage of the line, some sewers
last longer than others but generally normal sewers
under normal conditions last about a year before
the soap and grease reclogs the line so if you
snake it at about 11 months before it backs up again,
you will save yourself another mess of the dirty
water backing up
We would not recomend putting any acid type drain cleaners
into the drains because what usually occurs is a weakening
of the pipes, making them leak from the acid content of the cleaner
resulting in a replacement of the pipes in the near future.
