Here is a photo of my 40 year old cart kettle grill which I have just rehabbed, almost as good as the day it was purchased. I didn't take a before photo, oh well! The grill has sat out for 23 years uncovered in Chicago weather.
I also have a Weber gas grill that is about 25 years old and will probably rehab next year, parts are always available through Weber parts which I have used in the past. I will definitely take before pictures when I rebuild the gas grill. Also I never cover the gas grill because I use all year round.