Steep roofs generally collect lesser debris and leaves and hence moisture does not get accumulated and does not give fertile space to the moss or lichen to grow. This makes steep roofs safe from damage caused by the elements of the nature but not completely as apart from rain and hail, there is sun light also could adversely affect those steep roofs with you shades. So if you have got steep roof for home, make sure that it is well protected by sunlight. I have written a micro blog of sorts on this topic, please do review it and give me your views: http://mydfwroofer.com/importance-roof-pitch/
Agree that steeper roofs last longer.But if certain sections never recieve sunlight due to its steepness, than that is Not good due to the sun not killing algae, sealing shingles properly, rotting out fasteners..
Yes and that is why proper ventilation is extremely necessary and also these roofs need to be regularly inspected to spot the problems while they are at infancy.
Not if hail comes in sideways.... then you have 1 side blasted and the other well, NOT getting paid for by your unsurance adjuster.