Oh, I still use tabs. but set the indent width to 3 spaces. Saves as a tab, but displays as three spaces.

You missed the most important part. Spaces are spaces. Tabs are tabs with a tiny, obvious tab marker in grey.

Look how obvious and imposing those evil tab markers are!

{"name":"kdev-kernel-3.png","src":"\/\/djungxnpq2nug.cloudfront.net\/image\/cache\/6\/3\/63ef2259d0bd50cca2e6ebf254cdede2.png","w":757,"h":704,"tn":"\/\/djungxnpq2nug.cloudfront.net\/image\/cache\/6\/3\/63ef2259d0bd50cca2e6ebf254cdede2"}

If only they were spaces the code would become immediately more readable.

Were you expecting something like this?

{"name":"1RgHzFX.png","src":"\/\/djungxnpq2nug.cloudfront.net\/image\/cache\/2\/b\/2b47cb23489f0e7dff87f451550a45e5.png","w":757,"h":704,"tn":"\/\/djungxnpq2nug.cloudfront.net\/image\/cache\/2\/b\/2b47cb23489f0e7dff87f451550a45e5"}

Tabs are awesome.

It's not really tabs vs spaces anyway. It's tabs vs 1 space vs 2 spaces vs 3 spaces vs 4 spaces ... I once worked with a guy who used 40 spaces. He literally hit the space bar 40 times. His argument was that it looked the same on everybody's screen. I couldn't really think of any counter arguments, so I guess he stumbled across the perfect setting.

Anyway, if you really must see X spaces per tab in a terminal, you can just pipe things through expand -t X.

Those markers are so subtle I imagine you could easily make mistakes even with those showing. What does it look like with indentation errors?

I still press the tab key, my editor just puts in spaces.

set softtabstop=4
set expandtab
set shiftwidth=4

My editor knows to use real tab characters when editing makefiles*

*makefiles are primitive compared to cmake/scons so I rarely write makefiles in the first place.

set pastetoggle=<F2>

Though I honestly rarely paste code... I don't believe in copying/pasting code... If the code is that similar then you should write it once in a reusable way... Which may not include some repetitive patterns in code, but I don't copy/paste those either. I yank/put them or macro/script them...