Which is correct? One space or two spaces to start a new sentence?

Two spaces was taught in typing classes, but it probably doesn't matter any more.

2 is what your suppose to do, but you just keep doing you man. Dont let the tyrant hold you down!

Use one space.

Two spaces was a thing necessary on typewriters.

One. Always one. Unless you're seventy years old

MLA standards change every year as do all of the "standards". So, space your sentences the way you prefer.

Except for pretentious and anal pricks, no one will notice or care if you use one or two spaces between sentences.

I'm in my 20s and was always taught two spaces. It isn't just an old person thing.

I have always used two...and frankly, I am not plannin to devote the effort necessary to break that habit any time soon.

Neither. It's one space to end a sentence. Zero spaces to begin one.

1 space is for slackers

2. Kids these days....