Cast Iron Drain Line Issues
First, they corrode. Ans as they get older they tend to develop pinhole leaks. Also, most of the solder used for them was lead, so working on them can be unsafe for the average home owner.
Also, stuff tends to stick to the sides of the cast iron and eventually limits how waste drains. It is also very brittle as it ages and can break easily.
If you are having trouble with cast iron pipes, then consider switching to PVC. I am a licensed plumber serving Margate FL and all surrounding areas. So contact me and I will be happy to help!