I've used emacs for decades and always wondered, but kept on coding, if there was a way to type in something, them move the cursor and insert the same text, like the VI . command.

Instead what I do is to type the text, set the mark, backup, copy the region, go to the next spot (often just C-n, down one line) and then pre-arg yank, C-u C-y.

It's the overhead of set mark, backup and copy region that makes me just go ahead and retype the thing.