I also don't think people are factoring in the time to buy the oil, clean up, transferring used oil to a container, and recycling it.
Well, in my case, buying it involved a two minute detour from the food section of Walmart to the automotive isle. Clean-up and transferring is part of the 20 minute DIY oil change process, hardly a deal breaker. Recycling involves keeping a five gallon container in the garage and storing dirty oil until it gets full. Then it's off to any parts store and a quick dump into their bulk tank. This happens about once a year, and I do it while running additional errands.
None of this means anything when your pull over for the check engine light, and learn that the monkey that changed your oil failed to tighten the drain plug, and you need a new engine. Or any of the other half dozen common screw ups that are typical in the "Quick change" business. (Stripped drain plugs, double gaskets on filters, over torqued drain plugs, releasing the car to the customer with NO oil in the crankcase, overfilling, and more) If you are a like many here, and are planning to drive a vehicle till the wheels fall off at 300K, regular oil changes are a key part of the strategy. Wasting time and money at the Jiffy-Lubes of the world isn't the best way to get the job done. For a lot of us, circumstances require subbing it out, but if you got the time, tools and space, it makes no sense to risk it by not DIYing.
As for coupon changes for $19.95, at that point the work is a loss leader that is being done below cost in hopes of upselling. For your twenty you are getting service performed by a semi-skilled helper who is far from being a trained mechanic. You are getting bulk oil that you know absolutely nothing about, that may not meet ILSAC quality standards required by your vehicle manufacturer, and is the cheapest crap that the business can find in volume. You are getting a filter that, most likely, doesn't even come close to matching any OEM specs. and is not approved by the vehicle manufacture, as it is made from inferior material, and cannot meet filtration micron requirements. I spend $6 for an OEM filter for my car, but I can spend as little as $1.92 for an "economy grade" will fit filter. That price is for a single filter, not the hundreds that a quick lube shop buys at a time, for even less than $1.92 It may be a third smaller than a factory part, and only capable of filtering debris that is several magnitudes bigger, but it's a filter, and when you are trying to scam a customer in the door without losing your ass, your only quality requirements for a filter is, "is it less than $2 and does it screw on? Nothing personal, but at $20, unless you are driving a $500 POS, you are only shooting yourself in the foot. It's tough to find decent dino oil and a quality mid-grade filter for $20 to DIY the job, paying somebody a $20 to do it in a shop isn't always going to end well.
