Your sewer line is only four inches wide. Anything that doesn't break down like toilet paper eventually catches on a root or joint.
Never flush
Wipes of any kind, paper towels, cotton swabs, dental floss, cat litter, grease, medication and feminine products.
In the kitchen
Keep grease, coffee grounds, eggshells and pasta out of the disposal. Scrape plates into the trash and run cold water for 15 seconds after grinding.