I find the "repeat-n-times" modifiers require a lot of thought before I know what number to put before the command. I do consider myself very fast with Vim, but the repeat commands haven't done much for me.
- Run the command once
- Think "Hmm, looks like I have to do this about ten more times"
- Type '10.', repeating the last command 10 times
- See that there's only one left to do, since you guessed 10 and it was 11
- Press '.' one more time to do the last one
You won't win any vim golf competitions like that, but it's very easy to do.
I still haven't found an easy way to indent a line N times without pressing ">" 2N times...
I will record that macro, then repeat it 100 times. Since every command includes a movement at the end (say, a "j"), this will change 100 lines (or words, or regex finds, or whatever).
Damn, I instinctively hit <ESC> after writing that last line.
Occasionally I know I want to delete just 2 words and so use d2w or something, but that's so rare I really notice when it happens.