My tree is usually mismatched 'tat'. I have attempted themes in the past but then think 'oh I can't leave that off....or this' so I end up with our much loved and mismatched bits and bobs yet again. I always put on the decorations the children have made (and they've made a lot 
) but some friends of mine won't put their children's makes on or put them on 'round the back'. Even when said children were only 3 or 4 and were very proud of their efforts.
Neither way is right or wrong, everybody has to please themselves in their own home. I'm really not judging (I am in fact jealous of the beautiful trees my friends have!) I was just wondering what is the norm.