For me, it really depends on the ages. For the really young kids that I have now (all under 2), crafts are only available at a specific craft time, which I do with them individually. As they get older (junior preschool and up) things will open up more. Once they hit junior preschool age, I'll let them have crayons and paper. By this age, they usually understand not to eat the crayons or write on the walls and floors. Under close supervision, and if everyone wants to participate at this age, I will bring out safety scissors, magazines and glue sticks too. At Senior Preschool age, I'll leave out crayons, markers, paper, glue sticks and maybe some collage materials for them to use at their leisure. Sometimes, with the older kids I'll also leave out some pipe cleaners, egg cartons, toilet rolls (whatever you like really) and let them be creative with them. I don't allow the kids to just go hog wild on ALL craft supplies as they tend to be expensive and they'll often just leave stuff after a minute of mucking about. I've found, too, that having too many options isn't always a good thing. The next thing you know, you're craft area is torn apart and needs serious reorganizing after just a few minutes of little hands checking it out. Painting is a supervised activity at any age, and usually has a specific time allotted during free play during which I can help them with smocks, paper set up, etc. With the little guys I have now, I stand with them while they paint, otherwise it's on them, in them and on everything else.

I worked at a Reggio themed daycare once on placement, where the kids were allowed to ransack everything, all the time. That's fine if you have lowly students to clean up the carnage afterwards