I prefer to do my own regular oil changes, and only take my car to the mechanic/dealer for significant servicing milestones (e.g. 30/60/90k). Each time I change the oil, I can't help but feel that I've skipped checking something important. What is a good checklist to go through for routine oil changes?
Staring with my own list:
Don't forget to change the oil drain plug gasket/washer. Particularly if it's a "crush washer". Even on the copper ones that you can re-use a couple of times, I just replace them every time. When I get oil filters for my cars, I also get a washer for each, and tape it to the filter box, so it's right there when I need it. I usually do this right where I buy them, they'll usually have tape they can give you a few strips of.
I also always coat the filter gasket with some oil to help it seal, though there's probably enough from the removal of the previous filter to make that not a big deal.
If the filter goes in open side up, I will fill the filter with oil so that on re-start it doesn't have to pump as long to get oil circulating. On older cars I've done a trick recommended by Pat Goss which is to ground the ignition coil input and crank the car for a bit to circulate oil, but I'm not sure how I'd even do that on my car that has 8 coil packs, one mounted to each spark plug. It's probably riskier to the electrical system than the engine wear it saves would be worth.
Some people recommend sending an oil sample in to a lab to have analyzed, every couple of years... I've never done that though.