Renting a car (in the US) can cost $40/day.[a] That’s how much gas costs me in a week or so. It’s not cheaper to rent.

[a]: Don’t forget the $150-300 deposit (that takes a week to disappear). And also being pressured to pay for their $15/day insurance. Rental companies are expensive

The cost of a car isn't just gas, you have to amortize the cost of the car depreciating, the maintenance, registration, etc. For a quick example, https://www.nerdwallet.com/article/loans/auto-loans/total-co... has a monthly cost of 690 using average (used) values and 0 dollars for gas. So you can drive 17 days a month and still come out ahead renting. There are services like zipcar, or [hourcar](https://hourcar.org/individual/) that make renting significantly more convenient, though the costs are marginally higher if all of your trips are full day.

I've done this calculation multiple times in my life, and because I mostly get around via bike (perks of living in college towns which have to invest in non-car infrastructure), its never been worth buying a car.

I spent $4205 on car expenses last year, not including fuel (since I'd pay fuel separately on a rental car as well). That's for two cars (spouse & I), so I'll say $2100 per car.

The cheapest rental car I could find (searched kayak.com) is $72/day.

So, renting could only be cheaper if I used a car less than 2100/72 = 29 days per year.

But that's not counting cost or inconvenience/time of getting and returning that rental car. The few times I'd had to rent a car I've had to get an Uber ride to get to the rental place and then back home, so that adds another $20 or so to the rental.

> Renting a car (in the US) can cost $40/day.

I just looked up (on kayak.com) the cheapest rental car I could get tomorrow and it is $72/day.

> it's much, much cheaper to rent one

It’s much, much more convenient to be able to go where I want when I want.

Hiking, skiing, my friend’s cabin, the lake house, my friends in the suburbs, Costco, that speciality root beer store I like. I don’t even need to plan my trip. I can go whenever I want.

Yes you can rent a car to do those things. But it is indisputably friction. My experience is that my friends who don’t have cars are subsidized by those who do. Either that or you don’t see that friend because public transit makes it too inconvenient.