Killing a kit

I've never referred to using all or most of something, with that terminology.

I would never leave a kit intact, that is just not my style or way of doing things.
If I purchased a kit, it would immediately or within a reasonable time frame, get sorted into whichever category it's going. Whether it was all going in one category (like Christmas) or into multiple categories.
If something didn't fit in a specific category, it would go in the miscellaneous binder or miscellaneous paper holder.

I store the majority of my stuff by theme(Christmas, outdoors, entertainment, food, vacation, etc...). I have about 30 or so themed storage categories (13 x 13 plastic storage envelopes).

I've never bought monthlykits, but I do buy themed collection packs, like zoo or Christmas.

I consider it finished when it's nothing but bits left. A sticker or two, just small paper scraps.

Then I put those bits in the two gallon Ziploc bag with the rest of that theme.

Or I'll make one last layout with all those small bits layered with coordinating paper strips against the left side edge of the background paper, then leave the right side with lots of white space to add a photo, small title, and a little journaling.

I would say it’s killed when most of the papers are used up and nothing is inspiring me. I’m working through an elles studio monthly kit now. I feel like it’s multiplying as I use it. I think I have made 4-5 project life spreads. I have 2 cards I might use up still but another 3 are probably getting trashed as well as some of the embellishments. I’m close to calling it killed. It’s cannot revive it with anything interesting.

For me it’s when I’ve used enough of the coordinating items until there’s just bits and pieces that don’t go together. Sometimes it’s just scraps with random ephemera or it has been a full page or two of paper that just didn’t work with the others. I put it in my stash then and the items I won’t use since I just don’t like it goes into the donate pile. I don’t get kit clubs anymore since I didn’t use them (until I forced myself to this past year), but I do at times end up get sucked into buying entire. Collection and I end up doing the same thing there

I like to mix companies so I don't do straight kits. And I like to mix between a company. Just how I scrapbook. Not a strick line/kit person.

when i've cut into at least 3/4 of the papers. 

I'm still using up a kit from 2010 and I agree, the paper seems to be multiplying the more I use it. That being said, if I use at least 70% of the kit I consider it "used up" and will either add the usable parts to other kits I've made or donate them or give them to my daughter. I usually get tired of using the same kit for too much so I've found 70% usage of the kit works for me.

Depends on the kit. Depends on how I tend to remember that kit.

If it is distinct and I love using it, the remnants stay in that ziploc bag together until there is barely anything left to use.

Sometimes after I have created a couple of layouts from a collection, the remainder goes to join their friends in a theme category. So red/green/gold Christmas lines all end up together in my Christmas tub; blue/silver in a different location, same tub. All my FALL/Autumn lines end up together, with separate but close places for School and Halloween. Doesn't matter what kit they came in if they all work together.