I've skimmed through about 100 posts about Forester head gasket failures and I get the feeling this is a stale, boring topic.  My 2006 Forester (only 67,500 miles) is dripping a few drops per day from the passenger-side HG and the driver side shows a stain forming.  I'm out in Colorado where labor rates are pretty reasonable.  Questions: 
 
If I have the head gaskets replaced with "good" quality parts, how many miles can I expect to go before I have leaky gaskets again?  Best guess? 
The leak is minor for now.  Does it make any sense to wait for the leak to get worse before servicing? 
 
  
Thanks -- really enjoy this forum. 
Mark