The easiest way to hang Christmas lights on your roof is to attach them to your gutters, but there are plenty of user-friendly methods to try. You can use light clips to easily hook Christmas lights to your shingles, eaves, gutters, or soffit. However, using a telescoping pole is a surefire way to ensure your safety while hanging Christmas lights because it doesn’t require using a ladder or climbing onto the roof.

Several options for hanging Christmas lights won't damage gutters. Using shingle clips avoids any hardware contact with them, and using plastic gutter clips minimizes the likelihood of scratching gutters. Remember not to rest a ladder, especially a metal one, against the gutters, and use a ladder stand-off device or stabilizer if you need to use an extension ladder. 

How many string lights can be on one outlet depends on a number of varying factors, including the total wattage of your circuit, the type of lights, the energy needs of the lights, and cord specifications. It’s better to play it safe here to protect your circuit, so figure out the max wattage of your circuit, compare that to the lights, and move on from there. Generally speaking, LED string lights require less energy than incandescent bulbs, translating to a higher number of lights per circuit. 

If you need to visually inspect your Christmas lights to determine which are good and which need replacement, there are a few things to look for. First, look for discoloration, such as a dark spot or two on the inside of the glass. The spot is an indication of a burnt filament. Also, look for missing filaments, cracked bulb glass, and broken sockets.