Last time I got my oil changed, I had Amsoil full synthetic put in. I'm just wondering at how many miles I am good for before changing? I've heard some different things from friends, but someone please set the record straight! Thank you.
with a good quality oil filter like K&N or Mobil1 you can easily go for 7500 miles ... do a search and you'll see tons of threads about the OCI (Oil change Interval)
The only way to accurately determine the life of your oil is by doing UOA. But yes, full synthetic can run 7500 miles with no problem (that's my oil change interval).