This post is about the thing in the title.
I used to work for Yelp. For historical reasons — probably “the initial developers preferred it” — their mostly-Python codebase had always been indented with tabs. That’s in stark contrast to the vast majority of the Python ecosystem, which generally uses the standard library’s style guide recommendation of four spaces. The presence of tabs caused occasional minor headaches and grumbles among the Python developers, who now numbered in the dozens and were generally used to spaces.
At the end of 2013, I bestowed Yelp with a Christmas gift: I converted their entire primary codebase from tabs to four spaces. On the off chance anyone else ever wants to do the same, here’s how I did it. Probably. I mean, it’s been two and a half years, but I wrote most of this at the time, so it should be correct.
Please note: I do not care what you think about tabs versus spaces. That’s for a different post! I no longer work for Yelp, anyway — so as compelling as your argument may be, I can no longer undo what I have done.