My 1955 house has a 25 foot drain run from my kitchen to my main stack (~7 feet of bends, then ~18 feet straight along a back wall).
It has clogged several times in various places, and I have had it professionally snaked as well as doing it myself.
The clogs are mainly grease - the only solids are the food bits that make it through the sink strainer. I don't have a garbage disposal, and I've been told I shouldn't install one in this kitchen due to the drain.
The drain tech said that we could just expect to have it snaked once a year or so - his best recommendation was an enzyme product to digest the sludge in the pipes.
I'm hoping I can do better than drain cleaner products by installing a grease trap to intercept most of it before it settles in my pipes. From what I've read, grease traps are common in the commercial/industrial/restaurant sector, but they seem to be rarely used in homes.
Is this a good idea for my kitchen? What are the criteria for installing a grease trap?
Besides the under-sink space and periodic cleaning, what are the drawbacks?