I don't help at all unless my kids ask for help (and need it, as opposed to wanting me to do the thing for them). If they do need me I'll help them understand how to do it and I'll get supplies but I won't do any part of the actual project for them.
I'll never forget the time I went to my 3rd grade son's class for a parent-teacher conference and she had all these pioneer style covered wagons on display. They were incredible! Wooden spoke wheels, canvas covers, tiny model barrels and crates within, etc. There sat DS's cut open milk carton "wagon" with tinker-toy wheels, a piece of copy paper for a cover and some Lego barrels full of Lego food. I was embarrassed. I had offered to help him a bit but he'd refused, said he could do it on his own. Clearly the other kids had had help. I felt like explaining to the teacher "I
offered to help him, really!" but I kept my mouth shut.
When we were back in the car DS said "Mom, did you see the other kids' wagons?" and I thought "Oh man, here it comes..." He said with pride "They SO had their parents make their wagons, don't you think? Not me, though, I did mine!"

That same year my DD was in 5th grade and entered the Science Fair. Again, I did not help except to purchase her requested supplies and hand them to her (the only help she'd requested). When we got to the fair you could see that some of the experiments were amazing, real scientific stuff. Ornate displays, extensive typewritten papers, etc. My DD's poster was a little sloppy, she had handwritten her proposal, notes and conclusion on notebook paper. This was a k-12 charter school and there were awards for each grouping (elementary, middle and high school) and then one overall award for the very best project, judged by three of our teachers and three from the local school district. My DD had won that top honor. I cannot tell you how proud I was, heck still am 2 years later. Her experiment wasn't the most high tech, nor did it have the cleanest presentation, but dang if it wasn't
hers, idea through execution, and she rocked that puppy!