1)Is it something to be unduly concerned about ? Not in my opinion. But everyone has there own opinion. The name 'asbestos' siding is a bit misleading. Yes asbestos fibers are encased in it. But the amount of asbestos in it is small and it isn't friable. It shouldn't be sanded or broken. But I wouldn't compare it to asbestos insulation. 2)Will it affect the resale value ? Depends on your area. You happen to be worried about it. Is everyone else in your area of the country? I have it on my house. My house is surrounded by houses that have it. You'd be hard pressed to find a house of that generation in my area that doesn't have it externally or covered over with other siding. So the answer in my area is no it doesn't effect resale. 3)Are abestos certified contracters very expensive ? Generally, yes. For siding, they may not be as expensive. In some jurisdications you can remove it yourself by wetting it down, removing it with minimal breakage and letting the dumpster company know it is in there.