Sink drain
Most common sink drain problems: Grease - Soap - Food
If we are talking about the kitchen line, the cause of blockage is most often food residues (such as rice, pasta, etc.). These products expand in the pipe, creating a plug.
To avoid clogging the pipes with food waste, see my recommendations in the Garbage Disposal section.
Another cause of blockage can be old pipes. Pipes made of cast iron, over the years start to erode and make it difficult to flush smoothly. If you have cast iron pipes, it is not recommended to use blockage cleaning products containing acid. Acids may remove the blockage, but the pipes will continue to deteriorate and eventually be unusable.
To keep your pipes in good condition, you can use products containing live bacteria. These bacteria will prevent blockage and create a protective coat on the inner wall. This product does not work immediately. If the blockage has already occurred, you need to clean the pipe mechanically. But as a preventive measure, this may be the most optimal solution.