The largest problem we see hands down, bar none, is with Gutters. Short and simple; if you have small 5 inch gutters with spike nail heads showing on a 15 year or older home, its probably time to change them out. But don't trust this article look for yourself. You don't need to be an expert to tell if your gutters are shot.
Go outside when its raining pretty hard and see if your gutters are over flowing. If they are you have a problem. Check your down spouts make sure they are not clogged. Check the drain pipe in the ground to make sure its not clogged.
Look for rotten wood at the corners of your fascia. Rotten doors, windows, frames, brick molding and siding are huge signs of gutter problems. Look for evidence of dirt, pine straw or mulch that is washed away.
Look for wavy or dips in the gutters. A gutter should tilt toward the downspout.
Look for gutters that are bent forward or pulling off the house. An empty gutter does not weigh that much, but if its full of water it can weigh a few hundred pounds depending on the length. That weight can pull the gutters off of the house or break the fasteners holding them up.
Sometimes all an older gutter system needs is a good cleaning, but be careful. I don't know how many times we have gone out to a home where the gutters were recently cleaned, but still needed to be replaced. We had a case where the gutters were pulling off the house, rust holes, leaking at the miters (corners), miss aligned, missing nails and not big enough to begin with; yet a company still cleaned the gutters out and got a check.
Is it possible to repair older gutters? If you only have one or two small areas that are leaking or dumping water you can try to have them repaired or cleaned, but usually we see multiple areas that have issues. My advice is if you see multiple areas with problems, gutters are nailed up, 5 inches or less and 15 years or older its probably time to have them changed.
Most of the homes in our area, North Atlanta, used small 5 inch gutters when they were built. A 5 inch gutter is too small for most of homes in our area. They get full of water and pull off the house in many cases. Many of the gutter systems were installed with large nails or spikes, galvanized steel gutters, which rusts, and not enough down pipe. All of that plus multiple leaks, clogs, or overflow areas means you probably need new gutters.
A 6 inch gutter holds almost twice as much water as a 5 inch gutter.
Today we use big 6 inch seamless aluminum gutters, hidden hangers with screws and 3x4 downspouts. The gutters also come with a factory finish to match the color of your home. We use common sense and building code to figure out the best way to install your system. Sometimes we need to use larger gutter and more downspouts to handle the amount of water in an area. So don't be suppressed if your gutter man wants to change your system a little bit.
Look for a gutter company who will repair and paint rotten fascia. Always, always, always repair rotten fascia or rafter tails before you install new gutters. We have seen gutter companies put brand new gutters up over rotten wood before.