Two things:
1. grease build up happens even if you are careful.
2. Saurkraut should not be disposed of in your sink disposal!
After 25 years in this house, and NOT ever pouring grease down the the double sink, there was an unknown almost obstructed pipe about 15 feet down stream. It accumulated from the minuscule amounts of grease that remain in pans and pots, and from organic leftovers from meats and some veggies.
Then unknowingly, I disposed of a quart of sauerkraut in the disposal, and ended up with a plug, down the line. I first thought it was where the two pea traps emptied in the common drain under the sink. But was unable to dissolve this with Drano, and also a 12 foot wire snake. I called my friendly plumber.
When I told him what I had done, he shuddered and said "never, ever, ever, ever, put sauerkraut down the disposal". At least not more than just the few strands left on dinner plates. He was surprised to find that the pea traps were open, so he ran his electric snake and found the obstruction 15-20 feet down stream, apparently at a turn angle. It was all hard grease with sauerkraut completing the process, at least that is what his snake tip contained on removal. He successfully cleared it. Instead of a one hour charge, it took 2 hours all together. $302 later, he left with this advice:
1.No sauerkraut down the disposal, no oil or greasy stuff, and always let the hot water run after use for a minute or two.
2. Once a week or two or at least once a month, fill one sink with hot water, add a half cup of Dawn dish detergent, stir and then pull the plug. That should keep you grease free.
However, if I do nothing new, except omit sauerkraut, I should be good for another 25 years? I am 87 now, so I will report back on this when I am 112 years old.