Paint isn't just about looking pretty.
Exterior paint and stain works to protect your home from the erosion caused by sun and weather as the oil in your car works to protect it's engine from heat and friction. As old oil becomes less and less protective over time in your car, old paint also allows damage to your home.
The first visual sign that paint is losing it's integrity is a flattening and a blotchy look that is easily noticeable in the right light. This is paint that is being broken down by UV light and moisture from rain or irrigation. This paint is slowly losing it's adhesion and beginning a process which will allow moisture to break down the siding that the paint is there to protect. Even if it dosn't look all that bad, the paint is no longer a healthy protective coating and is on a downhill slide. It is time to paint.
By the time the siding on your house itself is showing through, your existing paint has ceased to protect altogether and your home has already taken damage and the aging process has quickened. Allowing a paint to be totally worn out before repainting is giving the new paint job a very bad start.
Fresh paint slows your home's natural aging process while keeping your home beautiful.
Protect your investment and avoid costly repairs by keeping a healthy coat of paint on your home.