Should synthetic oil be used in cars that have high mileage?

I heard somewhere that it shouldn't.Should synthetic oil be used in cars that have high mileage?
Well I think I can answer that for you, my car has 248,000 and the last 3 oil changes I have use full synthetic oil. With no ill effects I can tell, no leaks, runs drips or errors. I go for 5000 on an oil change,so that 15,000 miles with no problems. I did use the synthetic blend for over 100,00 before that. Any conventional synthetic oil should give you no problems, I did try STP when it first came out with synthetic oil and it caused my car to start leaking oil, 70's Granada w/302.Should synthetic oil be used in cars that have high mileage?
Synthetic oil was originally developed for high performance racing engines. Mobil tried to popularize synthetic oil for passenger vehicles back in the early 1970's. At the time, Mobil was promoting 20K or 25K oil changes with synthetic, but they soon backed down from this. Synthetic oil is a good choice if you have a vehicle with a high performance engine (in fact synthetic is required for many of these engines). It is also a good choice if your vehicle is operated in extremely cold climates. It has higher resistance to breakdown caused by heat and it flows better in extreme cold. Unfortunately for the synthetic oil industry there is virtually no advantage to using synthetic oil in a non-high performance engine that is operated in moderate climates. You probably could go a bit longer between oil changes with a synthetic, i.e. following the normal service schedule even if you fall into the severe service category, but I wouldn't advise this. In short, synthetic may give you the peace of mind of knowing that you are using an oil that is far better than necessary for your vehicle, but it won't reduce wear or extend the life of the engine. The mistake some people make it to wrongly extrapolate these benefits onto normal engines operated in mild climates, with the ultimate lack of any knowledge being manifested with statements such as ';synthetics provide 'Peace of Mind,' or 'Cheap Insurance,''; or other such nonsense.
My Accord has 240,000 miles on it and I change it with full synthetic every 5000 miles. Seems to have work great since I bought the car used at 160,000 miles. I don't have any oil leaks or anything and the engine isn't making any unusual noises.
it really dont matter but really it wouldnt help it any better than just changing the oil would you can use whatever you wish to run high mileage or not my car has over 300,000 still using regular oil
from what ive witnessed as being a mechanic for over 20 years is that it will not properly oil your engine if you have been using conventional oil. dont listen to what they say on tv