Length of login password on MacBook.

Correct, a longer password is just harder to guess. A login password isn't as critical as with an online password since someone can't easily automate the guesses when they have to be manually entered into a keyboard, but if your Mac contains really sensitive information, things that some criminal would be willing to spend time trying to access, I'd recommend a longer password.

Regards.

Hi,

I think even four characters password is safe if you use none letters like <+*&$.