Why does Python pep-8 strongly recommend spaces over tabs for indentation?

Well well, seems like everybody is strongly biased towards spaces. I use tabs exclusively. I know very well why.

Tabs are actually a cool invention, that came after spaces. It allows you to indent without pushing space millions of times or using a fake tab (that produces spaces).

I really don't get why everybody is discriminating the use of tabs. It is very much like old people discriminating younger people for choosing a newer more efficient technology and complaining that pulse dialing works on every phone, not just on these fancy new ones. "Tone dialing doesn't work on every phone, that's why it is wrong".

Your editor cannot handle tabs properly? Well, get a modern editor. Might be darn time, we are now in the 21st century and the time when an editor was a high tech complicated piece of software is long past. We have now tons and tons of editors to choose from, all of them that support tabs just fine. Also, you can define how much a tab should be, a thing that you cannot do with spaces. Cannot see tabs? What is that for an argument? Well, you cannot see spaces neither!

May I be so bold to suggest to get a better editor? One of these high tech ones, that were released some 10 years ago already, that display invisible characters? (sarcasm off)

Using spaces causes a lot more deleting and formatting work. That is why (and all other people that know this and agree with me) use tabs for Python.

Mixing tabs and spaces is a no-no and no argument about that. That is a mess and can never work.

The answer was given right there in the PEP [ed: this passage has been edited out in 2013]. I quote:

The most popular way of indenting Python is with spaces only.

What other underlying reason do you need?

To put it less bluntly: Consider also the scope of the PEP as stated in the very first paragraph:

This document gives coding conventions for the Python code comprising the standard library in the main Python distribution.

The intention is to make all code that goes in the official python distribution consistently formatted (I hope we can agree that this is universally a Good Thing™).

Since the decision between spaces and tabs for an individual programmer is a) really a matter of taste and b) easily dealt with by technical means (editors, conversion scripts, etc.), there is a clear way to end all discussion: choose one.

Guido was the one to choose. He didn't even have to give a reason, but he still did by referring to empirical data.

For all other purposes you can either take this PEP as a recommendation, or you can ignore it -- your choice, or your team's, or your team leaders.

But if I may give you one advice: don't mix'em ;-) [ed: Mixing tabs and spaces is no longer an option.]