I use one email for more than 5 characters. The method is to add a +[word] to your email address.
For example, if your email is email@example.com, when you are registering a 6th character you type the following as your email address firstname.lastname@example.org and it will still send the verification email to your actual email address (i.e email@example.com) and this gives you a further 5 characters to register. For every change to the word after the +, you get an additional 5.
Disclaimer: I only used this method on gmail.