I have read and searched but I haven't found a consensus opinion about this subject. Does a clean dipstick (after 1000 - 2000 miles) mean that the oil filter is doing a great job (and therefore a dirty dipstick means that the filter isn't doing it's job anymore) ? *OR* Does a dirty dipstick mean that the oil is doing a wonderful job of keeping the crud in suspension (and therefore a clean dipstick means that the oil isn't doing it's cleaning responsibilities and crud is building up in the engine) ? If a clean dipstick is better, then can we assume that an oil (or filter only?) change is needed when the dipstick starts looking dirty and as long as it stays clean (I am assuming the use of a quality oil with appropriate cleaning capabilities) then the drain interval can be extended ? I'm hoping that the answer to this is NOT "it depends", or, "only an oil analysis can determine still okay or not okay". What's my goal, always having a clean dipstick *or* being elated that mine is dirty ?