My 400' driveway was put in (21 years ago in New England) with 12"
processed gravel and a fabric to keep the clay from not coming back up
and mixing with the gravel and I never sealed the driveway.It looks
horrible with cracks and the center being higher than where the wheels
go. There is an underground stream that has helped mess up the driveway
as well. When I put it in I knew to let it settle for a year before
paving but didnt. I would not do it differently. but instead will have
a new layer put on top some day.If I had a small driveway and wanted it
to last as long as possible in a northern state and my time was cheap I
would seal it.