Grease is a coating, not a plug
Cooking fat goes down warm and liquid, then cools and sticks to the pipe wall. Over years it narrows a two inch line to the width of a pencil, and coffee grounds, rice and starch catch on it.
A cable snake punches an opening through that coating. Water drains, the visit looks successful, and the coating starts catching debris again within weeks.
What actually clears it
Hydro jetting scours the full pipe diameter with high pressure water, so the wall is left clean instead of perforated. It is the difference between a fix that lasts weeks and one that lasts years.
A camera inspection afterwards is worth it on older homes, because repeat kitchen clogs sometimes turn out to be a bellied or offset section of pipe holding water, which no cleaning method fixes.
Things not to do
Skip the caustic drain chemicals. They rarely pass a grease coating, they sit in the trap, and they make the line dangerous to open for anyone working on it afterwards.
Do not run hot water to melt grease down the line. It moves the problem twenty feet further along, where clearing it costs more.
Need a hand with this? See our drain cleaning & hydro jetting page, or call 626-386-9105.