I've got a little kid and a baby. Consequentially, my outfits have the following limitations:
1. Must be able to sit on the floor.
2. Must be either for cold weather or hot weather (i.e. no sweaters with shorts)
3. Everything must be machine washable.
4. Nothing must be ironed.
5. Tops should be light colors (baby spit up is white)
6. Tops are better without buttons (the baby rams his head into my chest sometimes).
7. Given the likelihood of destruction, I feel better if no item of clothing was particularly expensive (jeans and outerware are the exception.)