I have a 65 mustang 200c.i. 6 cyl. It gets driven 1000 to 1500 miles between may and october. I am using Rotella 10-30 with an autolite filter. In the fall I have been changing the oil and filter, and greasing the suspension/steering then adding a strong dose of Sta-Bil to the full tank of e-0 gas, then taking a couple mile drive, then putting it in my well insulated workshop/garage, and using fogging oil in the cylinders, and don't turn it over again till spring. My question is, am I just wasting oil/filter changing them every fall, or would I be just as well off going 2 years??? Some classic car sites even say change the oil again in the spring even if it just sat all winter, because it will have condensation. that has always seemed like overkill to me, as when I do drive it in the warm months, it gets well warmed up. So what do you guys say? change it every year like I have been, or go longer???