First, attic temperatures can fluctuate widely, which can shorten the lifespan of your lights. Second, attics can be dusty places, and if the lights are not in airtight boxes, the dust can build up on them and cause them to malfunction. Finally, if you have pets or small children, there is a risk that they could get into the attic and damage the lights. Overall, storing Christmas lights in the attic can be convenient, but it is important to weigh the pros and cons before making a decision.