Originally Posted by Ariana:
It sounds like your set up needs to be more kid friendly. I wouldn't be able to take care of children and help them develop if I couldn't let them move around freely and explore art. Why not set up an art area. make this area as completely kid friendly as you can so you don't have to worry. Table and chairs and then bins of washable markers and crayons. Almost everything on the market these days is washabe so I dont' sweat it! When a kid starts wandering towards your white sofa with a blue marker simply say "back to the art area please" 
Paint for us is a "special activity" which I prepare for the night before but crayons, markers and paper are always out.
I think I"m pretty kid friendly, but I do have limits. I think it's partly just the particular group I have. By the time my kids were 15 or 16 months old, I could trust them with crayons and paper, drilling "we only color on the paper" into their heads, and they did fine. I don't think any of mine ever colored on a wall or a book.
I have 4 kids (3 ft & 1 pt) from one family, and they are a wild bunch. I don't mind exploring, learning, etc. But, for the most part, toys are ignored, and I spend most of my time redirecting, even the oldest 2 (4 and 3). My 21 mo from another family I could probably (but wouldn't of course!), leave in the whole house alone all day, and it wouldn't occurr to him to push around furniture, climb up on a shelf, or otherwise trash the place. He would drive cars around all day if they (the other kids) let him.