I have a roof in Iowa that is 13 years old and is in need of repair--a 25 year shingle. Ther have been 3 occassions where shingles have blown off and they do not seal very well. I have a couple of contractors with different ideas to replace--30 year shingles which I do not think will last that long, metal roof either the agriculture smooth steel or shingle look, and the Mularkey 50 year rubber shingle. I am over 60 and do not want to replace the roof again--the Decera metal roof is very expensive but looks nice and has a 50 year warranty. The Mularky rubber shigle is somewhat less expensive than the metal roof but no one around here has it---any thoughts on this shingle (both cold and hot westher in IA) and overall cost vs longevity of the roof??