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Comment by bpodgursky | Hacker News Reader

The IRS deprecation is very far above the costs in actual practice. It's a very conservative number.

I think the IRS number might be spot on.

Quick math:

   ($25,000 cost to buy car new - 
    $4,000 residual value at end-of-life
   ) / 100,000 miles usable lifetime = 

   $0.21/mi depreciation of value

   $3.22 / gallon * (1 / (17 mi / gal fuel efficiency)) = 
   $0.19/mi for fuel

   Maintenance:
     $40 per oil change / 8,000 miles = $0.01 / mi
     $600 tire change / 60,000 miles = $0.01 / mi
     $1,186 average yearly repair / 16,000 average miles driven = $0.07 mile

That all adds up to $0.49 / mi and does NOT include insurance and DMV registration fees.

But in most cases, you aren't buying a car just to drive for Uber (more than half drive between 1 and 15 hours a week [0]), you're doing it on the side. Your per mile costs for driving for Uber are the marginal costs (costs of additional insurance, fuel, marginal wear and tear, etc).

Also, if you're driving for Uber in a new car that gets 17 mi / gal fuel efficiency, you're not making wise moves. There's a reason a lot of Uber drivers are using 5 year old Prius's - this cuts the fuel cost in half, and the depreciation down quite a bit.

[0] https://www.vox.com/2018/10/2/17924628/uber-drivers-make-hou...

Well, no, because if you are an Uber driver the vast majority of the depreciation in the value of your car comes from driving Uber. Cars depreciate in large part due to mileage.

Finally, "marginal wear and tear" is a completely absurd concept. The cost of wear and tear on maintenance of a car has a positive derivative and thus has no margin, the more wear and tear the more expensive wear and tear gets. In other words, the limit of the cost of wear and tear as wear goes to infinity is divergent towards positive infinity. Thus, there is no marginal cost.

In the real world, you can't spend an infinite amount of money on a car. There is a limit. The margin will come up at some point unless the driver is completely irrational.

Sure, but in the real world that cost is having to buy a new car, which easily increases the cost per mile by 50% and invalidates the point that "you were already driving a car".

It's an exceptionally poor strategy to drop $25k on a new car that only gets 17mpg when your intention is to be a rideshare driver. A purely internal-combustion Civic or Corolla gets twice that. A Prius more than 3x. So do the ones that are 3-4 years old already. And the Prius will probably last closer to 200k miles.

I would guess that the ridesharing companies will buy fleets before they'll pay Chevy Tahoe rates for compact sedans.

Huh; I had no idea that the newer Prius models can get 50 mi/gallon or more in city driving. That does change the equation quite a bit, I think.

Your cost per mile for gas is way off. MPG is way higher for typical Lyft/Uber.

Usable lifetime is also pretty low. A modern car can pretty easily get to 150k miles even driving Uber/Lyft based on the mileage I’ve seen in the cars I’ve ridden in.

Those are your two biggest factors in your calculations and you can cut them both by a good 30%.

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