If you read any manual on changing your oil, it’s going to tell you to let that thing drip for 15 to 30 minutes to clear out as much of the old oil as possible. Meanwhile, your average oil change place is advertising that they will have you in and out of there in 15 minutes from start to finish. Which means there’s no way they’re letting it drip the minimum of 15 minutes.
The soil change was so overdue. There is a difference between the service interval and abuse interval of oil. I definitely got into the abuse range on this occasion. I just didn’t have the money for the oil and the filter.
And while you’re taking care of your own oil change. Make sure to check your brake fluid engine coolant and washer fluid and top them off as necessary.
Full disclosure, when I was driving an ICE car I did all my own oil changes at home. However, 25 years ago I had to pay to have an oil change done.
The process this shop used was to empty the engine oil, put the drain plug in again, and fill the crankcase with new oil, run the car for 5 min with the new oil, drain again, then fill with more new oil.
In my mind, thats a pretty effective way to get the old oil out.
It will definitely help. But commercial places pinching their bottom line aren’t going to “waste” oil like that.