I don't, but mine are only 7. For now they get a or a check mark. Sometimes they want to know if what they did was an "A" or not, but I don't make a big deal out of it. I would think it may depend on the child and the level they are at, but mine are still young to where I haven't really hit that yet.
I did when I first started, but then decided I would rather have him fix things that were wrong than to grade them... so even if it takes doing the same problem in math 20 times, he eventually gets a 100% on everything.
i do and i don't. I put a grade on their work but i have them correct any mistake before they can move on. Their test are the only things i really grade and this is just so i can see if we need to review a concept before we can move on to the next unit. i don't give them any report cards and such.
I keep grades for some things. My oldest is going into 10th grade, and I feel they're needed at her level. I might also for some of my younger ones, too, like copies of their language tests, etc.
The first four or five years, I can't remember anymore, I kept grades because it was required by the program we were enrolled in.