Motorcraft synthetic blend or switch to full synthetic

If you can take advantage of extended oil change intervals, then that's a good reason to switch to full synthetic. But if you only change your oil once a year because you don't drive more than 5,000 miles a year, just stick with the blend.

I run MolyLube/LubroMoly full synthetic, but I also go as far as 12,000 miles between oil changes.