“Convenience” and “frugality” aren't words you'll often find in the same sentence. Unless that sentence is “convenience and frugality aren't words you'll often find in the same sentence.”
You're either going to burn a valuable favor from a friend who has a truck (and an able body), blow out your back trying to lift your heaviest furniture, or—best-case scenario—spend an entire day lifting, turning, setting down, washing, rinsing, and repeating.
Instead of changing the oil yourself, the mechanic already has a grease-stained shirt, an expert's understanding of changing the oil, and a readymade disposal plan for the old sludge.