Cold weather can cause older incandescent Christmas lights to fail by causing cracks in the finish or the glass itself. Modern LED lights are affected in the opposite way and perform even better as the temperature drops. 

You should always hang the lights before the ornaments because hanging lights on top of ornaments can cause some to fall off. If a light sits directly on top of an ornament, it can cause it to heat up and possibly change its color or cause it to crack. 

There aren’t many alternative methods to hanging Christmas lights on fascia without using clips. But if you don’t have fascia clips to hang your Christmas lights, you can use clothespins in a pinch. To do this, hold the strand of lights in place and clip it in place with the clothespin. Using nails or staples is never a good idea, as they can damage your fascia.

Yes, you can hang Christmas lights from the soffit of your roof, but it requires a bit more effort than hanging from the gutters or eaves. You’ll need to add an adhesive hook or tie to the underside of the soffit to keep the lights in place. Consider adding a soffit hook every 12 to 18 inches for best visual results.