I think what they are trying to say, is that if you have a huge max_length it is possibly because you accept any type of text, and you felt the number was high

I think what they are trying to say, is that if you have a huge max_length it is possibly because you accept any type of text, and you felt the number was high enough. If you use postgres, you want to restrict the length (even if it is 5000) ? => CharField, you don't care about the length => TextField