October 9, 2011the owners manual for my 2011 F-150 says 10,000 miles or one year depending on the type of driving you do and the oil life meter says it has 17% oil life left at 8,625 miles but the oil was looking dark so I am changing it anyway. granted almost all miles are highway and even in the old days of conventional oil you can go 7,500 miles between changes if driven highway (so they say) but I just cant bring myself to go the 10,000 miles.
I admit I grew up believing FIRMLY in 3 months or 3,000 miles but have come a long way in trusting synthetic oil. only reason I am so trusting of synthetic is co-workers saying how they change their oil once a year and have well over 160,000 miles or more on their vehicles that still run great.
just hope I have not done any damage letting it go so many miles but then I am well within manufacturer specs.