Also, brakes contribute to service unavailability. Brake pads need to be replaced on average every 50k miles, which takes the average driver 4 years. And let's say the average length of time your car is at the mechanic's to fix brakes is 3 days. That's 3 days of unavailability every 4 years just for brake pad replacements, or 99.8% availability (two nines!), just because of brake pad repairs. Add in all the other required car maintenance, and depending on the reliability of the vehicle, and you might be down into one nine territory.

Gmail going down is like your car being in the shop. It's not equivalent to a plane crashing; the equivalent there would be the entire contents and history of your Gmail account being unrecoverably deleted, and you yourself had no backups. Of course, I'd still much rather have that happen a hundred times than be in one fatal plane crash ..

Gmail seems to have 3 nines, although I couldn't find a better reference than this [1], where other services are included:

> [Google's infrastructure] delivers Gmail and other services to hundreds of millions of users with 99.978% availability and no scheduled downtime.

[1] https://support.google.com/googlecloud/answer/6056635?hl=en

PS. 99.978% availability translates as a downtime of ~ 2 hours/year total. Not bad! But it's when things break that we realize how performant and reliable they actually are.

Edits: various typos.

I'm consistently amazed how well Google and Facebook are at staying up. They're two services that I don't think I've really experienced a broad outage. Of course with Facebook's data designs, there's sometimes quirkiness as a result, but it's rarely completely off for me.

Google, I think I've only really noticed it offline once in the past 10 years or so. Not complaining at all.

Ok but like.... it takes <3 hours to change brake pads. So point taken, but numbers are more moderate than presented.