Considering you probably paid a lot of money for your sectional couch, you will certainly do your best to keep it in an excellent condition. How you will do that will mostly depend on the material the couch is made of. Leather sectional couches require a completely different type of maintenance than the ordinary fabric couches for instance. Leather couches require much less maintenance and if something goes wrong, if you spill something on them, they absorb the liquid much slower than the ordinary sectional couches.
This is why leather sectionals are so popular. You must only occasionally wipe them with a leather conditioner and that is it. If you have a fabric couch, you probably already know they get dirty pretty quickly, especially if they are in lighter colours. Well, the truth is, they get dirty as quick as the other colours, but naturally, stains on withe sectional couches stand out a bit more than those on black ones.
This is why the best maintenance for fabric sectional couches is just being careful. I know you wanted to hear some clever advice, but this is really the best I got. Considering how tough it is to wash them and considering you probably don’t want to have them wrapped in plastic, this is the best you can do.
Or better yet, get yourself a brand new leather sectional couch.