My house is 30 years old and has been painted at least 4 times, the last being 7 years ago. I have never used a primer on the masonite siding but see lots of articles saying you should use a primer. Since the body of the house has previously been painted and is in good shape (no cracks, chalking etc.) do you still recommend a primer for the body? I have primed all of the trim at this point.