I have a 2004 unit which I have only had for about 12,000 miles.I'd keep on with regular maintenance and when problems arise take care of it via a quality mechanic shop, don't go with the lowest bidder. The bottom ends are good for 300,000+ miles so have them do everything when it's apart and it'll be a good engine for another 100,000+ miles.
The original owner babied this one and I intend to to the same while I have the money! A local Ford dealer charges plenty, however they know what's what and I am pleased to do business with them in spite of the cost. I am an oldster and this will most likely be my last vehicle and so I need it to last as long as I do (I am 80).