All buyers should obtain a sewer inspection if the home in question is more than 20 years old. The line might be fairly new compared to homes built before 1950, but it's fairly common for tree roots to clog it up over 20 years or so.
Roots crawl into tiny openings and expand in the sewer line, latching on to other debris, such as grease or eggshell waste. This typically causes backups. Chemicals can sometimes kill the tree's roots, but the pipe itself might be damaged and require excavation to fix the problem.
Homes that were constructed prior to city sewers being installed often relied on cesspools. Sometimes these cesspools were left intact and connected to the sewer line after cities installed public septic systems. You won't know the makeup of your system unless you have the sewer inspected.
Many homes built in the 1950s have sewer lines made from tar paper. These are referred to as Orangeburg pipes, and they disintegrate and collapse over time. The sewer line definitely needs to be replaced if a home has Orangeburg pipes, and if the home is more than 60 years old, a sewer scope inspection is the only way to find out.