Even if you decide to leave your gutters as is, make sure that drains extend 5 feet from the house and that the ground near the foundation slopes at least 1 inch per foot for 6 feet or more to carry away water. Then keep these other points in mind:
Have a pro check them for clogs, corrosion, broken fasteners, proper pitch, and gaps between connections and between gutters and fascia boards. The LeafGuard and K-Guard are all-in-one systems that include the gutters and guards, an option if your existing gutters are worn.
Fine-mesh screens like the top-scoring LeafFilter and Gutterglove Pro outperformed screens with larger holes. But the Gutterglove was relatively pricey and hard to install, and the LeafFilter isn't meant for flat or gambrel roofs.
Be sure that any system won't void a roof or gutter warranty. Also check suggested maintenance. Some systems call for periodic hosing from the ground. LeafFilter may need brushing in high-pollen areas and Amerimax must be checked for debris; both of those steps mean climbing a ladder or calling a pro.
Ladder injuries are linked to approximately 200 to 300 deaths and an estimated 200,000 emergency-room visits each year. Use a sturdy Type 1A extension ladder made of fiberglass if you're working near electrical lines. Extend it 3 feet beyond the roof and angle it 75 degrees from the ground (1 foot for every 4 feet high). Always face the ladder when climbing and descending. And never go beyond the highest recommended step or reach more than 1 foot to either side of the ladder.