WEll.....after years of doing very frequent (3-8,000 mile OCI) oil changes, I'm going to leave it in for a year. I changed it last April with some Amsoil 5-30 (Signature Series) and have about 8,500 miles on the oil now. I did change the oil filter and add a quart of 0-30 Amsoil yesterday. So, thanks to BITOG, I am now getting my money's worth out of the oil I buy. Thanks Guys! I have now officially moved past the old 3K OCI mentality of yesteryear.