If you want to keep your home in tip-top shape (and avoid expensive problems down the road), you need to stay on top of home maintenance—and that includes your home’s exterior.

But what, exactly, on your home’s exterior needs maintenance, repair, or full-on replacement—and, just as importantly, when?

• Gutters. Gutters need regular maintenance to function properly and keep water runoff from causing damage. Plan to clean your gutters at least twice per year and, if they’re made from aluminum or galvanized steel (the most common gutter material), replace them after 20 years.

• Windows. Windows generally have a life-span of about two decades—but if you notice any damage to the glass or frame (for example, cracks in the glass or mold on the frame), you’ll want to replace them sooner.

• Roof. Depending on your roofing materials, your roof should last anywhere between 15 to 30 years (for standard asphalt shingles) or 50 to 75 years (metal roofing). But that’s only if you take care of it! Make sure to keep your roof clear of any overhanging branches that could damage the roof or cause mold issues.