Crafts is an activity that we have shared since she was a young child. It is a great way to spend time together and work together. It is amazing how quickly the time goes through these sessions. Now she is an adult and doesn't live at home but the rare times we share crafting are still very special to me. Now I often find that she is the teacher and I the student, a complete role reversal, and I love it.
I provide them with materials and let them go for it. If they need help with inspiration I help them come up with ideas. For things that are tricky, I work with them to help them achieve what they're going for with a piece.
My children have reached a stage where giving them instructions is enough for them to finish a craft project. I do enjoy making crafts with them though. I also enjoy taking them to craft workshops, especially at Bunnings which are free and give great ideas.
It really depends on the age of the child and what kind of help they require. Crafting is a lovely activity to share with your child, and while it's nice to see little ones learn to do things themselves (cut, paste or draw something), there are also times when they'll need adult assistance, especially with more challenging projects.
I think it's age dependent and also depends on the craft you are doing. I've always 'done' crafts with my kids, but my eldest son who is 3.5 yrs old is getting to the stage where for many of our simple crafts, he can just get on and do it by himself. For some things like cutting or the preparatory stuff, he'll still need my help, but for the imagination and creativity elements, he's good to go on his own steam. For more complex crafts, we'll maybe work together, but I'm careful of not to overstep and end up doing the craft for him, as I think craft time is a great vehicle for developing fine motor skills, independence and confidence or self esteem.
Only if they ask - I'm a fan of letting them do their own thing, and if it looks bad or doesn't look like it's meant to, it doesn't matter. We did an art class at the Art Gallery, and the other parents were basically making the craft for their kids or telling the kids they would 'ruin' it , if they didn't do it 'properly'. I work on the Picasso school of thought - they eyes can go wherever you want them to go....
I do it with my two grandsons. Basically they do it on their own but with supervision. The older boy (7) amazes me with attention to detail and the way he lays his items out on his project. For his recent birthday I included a couple of bags of different sized wobbly eyes. As soon as he found them he said "craft" so they will be in his next masterpiece no doubt.