What is the matter with a 18 year old unit? I love my 1995 Gulf Stream DP and as for annual Oil Changes, forget it. Do an annual Oil Analysis and go by that, I changed my oil last year based on the lab report and when I put it away for the season on the 29th, I will pull another sample and send it in and go by the report. The big trucking companies go by the lab reports and not by time and miles. By the way, I only use my rig about two weeks a year and only by a two month temporary tag for the two months I plan on camping. Next spring I plan on taking two weeks and head out to Virginia and then do the usual summer trips locally and will have to get one two month tag for later in the summer and just get a one month tag for the spring trip. I guess my point is it is paid for and I we enjoy it.