I’ve purchased brake pads at the auto parts store. Had to get a new gas cap once when my car failed an emissions test. It wasn’t leaking fuel, vapors I guess. Also a piston thingy to hold up the back window on a SUV.
Oil, filters, wipers, batteries and bulbs I just get at Walmart or where ever it’s the cheapest for name brand stuff.
Until 2008 I always drove older used cars.I used to buy more car parts back then. One of my favorites was a 1988 Ford Festiva. I replaced both axle shafts, the timing belt and water pump, brake shoes and pads, and the distributor. All those I got from an auto parts store. I also replaced the radiator but I ordered that online from somewhere. That worked out well because they sent me one for an automatic even though I ordered the manual one (radiators for the automatic trans had an extra row of coolant tubes).
I started buying new cars after that. I have had to buy two parts from the dealer - an axle seal from Toyota and tail light gaskets from Chevy. You just can’t beat Walmart for filters, oil, batteries, tires, and wiper blades. Auto Zone used to have a deal where you’d get a twenty dollar credit for every hundred you spent. I was able to take advantage of that once on oil change items, but then they changed it up and only let the credit for money spent accumulate for six months. I haven’t bought oil and filters in an auto parts store since then.
I think the notion that you can’t work on a modern car is somewhat overblown. While certain engine components are more computerized, there’s still a lot of car that’s perfectly replaceable for an average-skilled person such as the brake components, exhaust system components, etc. Even within the engine, there’s stuff you can still replace. For example, O2 sensor malfunctions are common enough and a brief look tells me that it’s not all that much of a fix with the right tools (namely a specialized socket). Biggest issue is loosening it if it’s corroded and stuck, nothing technical.
So, with the mindset that more on your car is fixable than changing the filters and wiping the headlights, it’s easy to see scenarios where you might want a part today rather than in 2-3 days. Either due to emergency or because this was the day where you found yourself with a free afternoon to work on the car.
Seriously, and more specifically, I’ve got headlight replacements, brakelight replacements, and turn signal replacement bulbs. Wiper blades. An alternator. Various belts. Tire sealant. Enough Bar-Leak to get to a radiator shop. Oil filters, air filters. Oil, transmission, and brake fluids. Gunk for an engine shampoo. A thermostat (installing that required the tools and help of a mechanic friend). A better jack than came with the car, and jack stands.
And lots of non-engine stuff. A rooftop luggage carrier. Primer and paint. A cigarette lighter. A travel coffee mug. Bungee cords, for use as tie-downs in a truck bed or the back of an SUV. A seat cover. And of course, air fresheners.
There are plenty of things that you can get at an auto parts store that have nothing to do with a computerized engine, and that you can still look after yourself.
As noted above, for every dollar’s worth of product going out the front door with a car owner, there is probably five or ten times as much going out the back to be delivered to professional mechanics. The front of the store is added revenue; not the main revenue of the business.
Two things I buy there that I won’t get online are batteries - because I can trade in the old one - and windshield wipers, since they’ll come out to the parking lot and put them on for me.
Out local Mobil does inspections and oil changes, and keeps almost nothing in stock, since the parts store is about a hundred yards away - if you fail wipers or bulbs they can go get the exact right one, and for an oil change they can get the right filter. And then mark it up.
FWIW, my visits to auto parts stores over the last 20 years have almost exclusively been to purchase/exchange batteries. The car won’t run without one and short of a tow, how am I supposed to get it to my mechanic?
The most visible “auto parts retailer” in the UK is Halford’s. They will sell you lamps, batteries and wiper blades, but a lot of their stock is related to minor body repairs and gadgets. The last time I was there was to buy a dashcam, which I paid them to fit. Before that, it was a battery for which they do a very good deal. They used to have a huge range of ICE upgrades, but that’s almost nonexistent now.
For the most part, anyone wanting a specific part for their car will buy online from a couple of reputable dealers or go to the main dealer for an OEM part. Main dealers offer a next-day delivery to local garages, and there are also parts places that only deal with the trade.
Granted I’ve reached an age where I don’t want to work on cars anymore but I’ll replace anything that’s “bolt on” . Gone are the days of swapping engines, replacing clutches or transmissions.
But I just replaced a battery that required the removal of windshield wipers, a cowling and miscellaneous parts. I wasn’t going to go to a shop for that.
I was surprised to see ammunition at a large well known Auto parts chain store in one of our Large Square states. I mean, I guess they stock what they sell, but I’m pretty sure the gun shops don’t carry wiper blades or headlights. I mean, where’s reciprocity when you need it!
I like the old school places, where they have at least a couple old guys or experienced guys. Auto repair and maintenance is kind of a perishable skill, a second opinion helps. They have some diagnostic tools they will test electrical systems for you, maybe some advice that’s worth thinking about. If you need more serious repair they might be able to tell you what shops they recommend or who they do not recommend, things like that. Sometimes you can even get a cup of coffee out of the deal.
I buy oil, car batteries, wiper blades, and tires at Costco. I buy OEM oil filters from dealers (lately online). I get polish and wax, replacement bulbs, license plate frames, and windshield washer fluid from auto parts stores.
I do my own maintenance work - oil changes, brake jobs, filter replacements, fluid flushes, belt replacements, bulb replacements, winter tire replacements, etc. Basically anything that doesn’t require a lift and can be done with jack stands I do it in my driveway. With 2 cars that means the Advance Auto Parts guy recognizes me when I come in the door.
Back when I was poor and fixed pretty much everything on my car myself, I bought a lot of different parts and tools from them. As I’ve gotten wealthier, older, and lazier I’ve started to take my car to others to have it fixed. As was mentioned earlier, there’s lots of stuff you can diagnose and fix yourself on a modern car. Even if it’s a proprietary code that’s being thrown, it’s possible to get the software to read those.
As for why one would go to the store and buy the part vs. ordering it online: sometimes you need/want the part today. I loved that my old house was less than an eighth of a mile away from an O’reilly. Even if I realized I needed something after I had the car apart, it was an easy walk to go get what I needed.
My little suburban area is littered with mechanic shops, tire shops, auto parts stores, car washes and gas stations. There’s at least 2 cars in every driveway. Plenty of people have a third “project” car. The American suburbs are definitely a culture that revolves around cars and the care & feeding thereof!
I agree with others that say a lot of the car part retailers are selling to mechanic shops. We’ve got a United Auto Supply that caters to commercial clients. It takes up one of the largest parts of the area’s old plaza (that spaces that used to be a Penney’s anchor store) and anytime I drive near that plaza I’m on the road with one of their delivery vans. They are BUSY.
Don’t forget you can also buy parts for your boat, RV, motorcycle and ATV, which owners might be more hands-on with than a typical car owner. Heck you can even get your occasional power equipment parts (spark plugs, lubricant, filters). Even in my immediate area of like 100 homes I’d say at least 60% have those sorts of recreational vehicles.