As mentioned, the only reason to utilize a full synthetic is for the longer service interval. They are actually less expensive than non-synthetics when utilized properly. For example, if you intend to change your oil every 3,000/5,000 miles, do not use a synthetic because the non-syntheic provide all the lubrication you require, but has a shorter service life. If you are going to extend your interval (I go to 20,000 miles between oil changes with a full synthetic) then the synthetic will actually cost less.

You should not allow you oil change interval to exceed a year. If you only drive the sportage 3,000/5,000 miles a year, stick to a non-synthetic. My 20,000 mile service interval is on a vehicle that sees 20,000 miles in a year. For vehicles that I drive less, I use non-synthetic and I change the oil once or twice a year.

FWIW.