My house was built in 1996, recently a roofing company came to me and repaired the air pipes. They just put a rubber hood over the old ones.
Sure enough, the guy who did the initial inspection told me that the entire roof needed replacing, and one told me that I needed more roof vents. The builder was very good and competent. Very high-quality subs and material to incorporate 25-year-old shingles. Although the gutters are partially covered with shingles, there is still a lot left on the existing roof.
My question is, when do you know when you really need a new tile?