Last year we decided to get rid of our old prelit tree. It was many years old and every year we were spending a lot of time getting the lights to light. And so at the end of 2016 we bought a new tree. However, when we put it up for the first time this year a large number of the lights didn't work in the mid section. I ended up having to remove that string of lights after checking every bulb and finding they all were good and buying a new string of lights to replace it. For awhile we missed our old tree.