In Denmark there is a law stating: when roads are slippery your car has to drive on winter tires. This law came into effect in 2025, but practically most people have changed tires for the winter season anyway. A similar law has been in effect in Sweden for ages. Every year it is the same story. By the first sign of frost, people rush to get their tires changed. Once spring comes, people rush to get them changed back. Demand peaks, and when the peak happens depends on weather - hence unpredictable.
Close to where I live there are two tire shops. One is part of a larger chain that also sells auto parts, bikes, and other things. The other is a small, local, independent shop that only sells tires, rims, and service. The chain has a booking system, the independent shop only offers drive in.
Booking
The chain has a fancy web page. This web page has a section for booking slots to get your tires changed. I have an account and the process is supposedly smooth. But on several occasions I have been unable to book a slot through the web page, and ended up having to wait in line for help desk. In those cases I ended up booking a slot through a human agent. When booking a slot, you never talk to the people that actually do the work. You use a system, or talk to an agent. Slots are predefined. That means they need enough margin (buffer, slack) in each slot to accommodate for any kind of variability. Tires are not stored on site, but have to be shipped to the store. Hopefully they make it in time for your slot. There is a single mechanic that does the actual job. The slot for changing tires already on rims is 30 minutes, the slot that includes mounting tires on rims is 60 minutes. There is a long lead time to book a slot, because most people book them well in advance.
Drive in
This is a simple model. You show up and first come first served. The independent shop has enough space for two cars. They always work in pairs. Mounting tires on rims, and then on cars, takes less than 30 minutes. Tires, tools, machines are all on site. During peak times the you might have to wait hours in line, but as long as you show up early enough during the day, you will get your tires changed the same day.
The mistake
I started as a customer with the independent shop. But I got annoyed with having to wait, sometimes hours, in line to get my tires changed. So I switched to the other shop, so that I wouldn’t have to wait in line. I recently switched back. Since the booking page didn’t work, again, I had to call helpdesk and book a slot through them. Demand was already high, and I had to wait ca 1,5 months to get a slot. As I needed my tires mounted on the rims, the slot had to be an hour long for one person to complete the job. I arrived for my slot, parked my car in the auto shop and went for a walk. After 10 minutes the stores calls me and says there’s been a mistake. The agent had only booked a 30 minutes slot, and that is not enough time to mount the tires on rims and on the car. So they will not change my tires, I have to book another slot. But with peak demand, I would have to wait at least another month. I came back to the shop, furious. I needed the winter tires, otherwise I would not be legally allowed to drive the car. So I loaded the tires into the car, and drove to the independent shop down the street. There was a long line, and they told me they would not be able to serve me today. But if I came back early next morning, and had patience, I’d get my tires changed. The next morning I had a quick breakfast, and was the first in line, 45 minutes before they opened. I got my tires changed, and was only a little late in for work.
Lean
I started thinking about these two models from a Lean perspective. With drive in only, you accommodate for variability. Tires, tools, machines are all on site to meet any kind of demand that comes in. They work in pairs to make sure throughput is as high as possible. I asked the owner of the independent shop if they have considered a booking system. He said that hey have, but can’t make up their mind. On one hand, he said it is very hard work during peak demand. They rush to change tires 8 hours every day and have way more work than they can handle. They do occasionally bring in extra staff, but it would be nice to get a break between jobs. They are obviously “sweating the assets”, with little slack in the system. But customers appreciate the drive in model, since there are few shops around that still have it. If you forgot to book a slot, or have an acute need to change tires (perhaps the roads turned icy before the slot you booked months ago) people accept waiting for hours in line. They actually get customers from the other shops this way (I was one of them). They allow for just in time decisions, when the job depends on something as unpredictable as the weather. It is not that one model is better than the other. The question is what you optimize for. If you, as a customer, don’t want to plan the changing of tires months in advance, you want flexibility, and have some patience, the drive in model is superior. If you want to book a great slot that fits your everyday logistics, with minimal waiting time, you make an upfront decision.
So now I’m back as a regular with the independent shop. Since I live close by, I can get there early. I get there 30 minutes before they open, and usually roll out with seasonal tires on less than 60 minutes later. There are of course many other factors that decide which shop to choose, like price (independent is more expensive) and quality (the seasoned mechanics at the independent shop are skilled at their craft). But overall, it seems like the world is strongly leaning towards a preference of pre booking slots for everything from museum visits, haricuts, restaurants and more. I think the drive in model of service still has good merit, even if I hate waiting in line.