It doesn’t do you much good to sell building owners on the long life span of a metal roof, only to have them call you a year later because the chimney flashing is leaking.
While many of the materials that comprise a roofing system have not dramatically changed in the past 15 or more years, many external needs of the building envelope have changed, and these revisions often should factor into roofing system selection — if not drive the decision-making process.