Common username conventions creating users for Azure Active Directory and office 365 portal

I'll start off with some background information

There is still some common misconception, I don't hear this too much from people in IT as much, but I was setting up office 365 for a small little nonprofit and they had less than 20 employees, when I started talking about Azure Active Directory they said wait a minute we don't want anything additional we just want office 365 for our email and some of the Office 365 apps, well if you're using office 365 you're using Azure Active Directory this is where the user objects are being stored even if you have a domain controller on site you're still using Azure Active Directory with office 365 and you can login to the portal and there's no additional subscription that's required.

Some reasons why we use conventions
One obvious reason is consistency and having consistent user names does make it easier when you're trying to find a user it's also easy when somebody says asks what's that person's email address.  It is very easy to say it is their last name first name. so

It is more professional
I don't know about you but I've had users come up to me and ask to use the one similar to their personal email and I have had some very strange request and of course they were denied 

Why do organizations use a specific convention for their Office 365 or Azure Active directory portal?
I found that the user name convention is often the preference of the first administrator that set it up.  When I've said well why they are you using a particular convention I often hear
well when I got here that's how it was set up. 

There are not many advantages in using one convention over another but there are some different reasons why you would want one convention and that has to do with the amount of users you're going to have or do have.  I certainly have my own preferences, what I like is to make the usernames easy to remember, easy to type in.  
How many users you have should dictate how you should have your convention, if you have a small user base for example I've talked with Active Directory administrators where they would say We have 150 people,  we use, first initial and last name and we have no duplicates.  But I've talked to other Office 365 portal administrators that have less than 50 users and they have multiple duplicate people with the same first and last name.  Sometimes you get lucky, but if you have a small user base your naming convention is not that big of a concern.

If it's a security-based user here's what I want to avoid. 

I don't want a user name with:
super user
If you ever looked at a log file of a system that has remote-access or a web server you'll see a lot of failed attempts for administrator, admin, superuser this is because there are scripts being run to try to guess passwords.  Either don't have these account names or make an administrator portal account but it's not actually an administrator account it’s a honeypot.

If you have lots and lots of users you will have duplications with the large user base and you're going to have to be flexible because you're going to have to have a convention for your duplicate users but then you'll have to have a convention for your duplicates of duplicate users.  I was setting up an online system for a school and this is actually more common than people know or would kind of guess but the father has the first initial and so does a mother, then they decide to name all their children to have the same first initial and they all have the same last name.  I've come across this a lot so if you're in a school environment and use the first initial last name you will have many duplicate user login names.

I know one college that asked all their new students for four random digits and this cuts out duplicates, but how would you like to be that IT department or probably the student IT intern that had to type all those in.  How many mistakes do you think they made when they were typing it in, I'm willing to bet there was a lot of students that gave the four digits of their PIN number, social security number, or their phone number.  I think there's a better way to stop username duplications and save from having this big tasks of typing in these numbers.

Invalid characters in Azure Active Directory and Office 365 portal usernames
When you create a username in office 365 there are certain characters you cannot use and when I read this list I was I thought there's no big surprise here but then I read the list again. Wait a minute, hyphens are on this list and I've seen hyphens, and I've used hyphens, this list must be wrong, well there are some exceptions when using hyphens in Azure Active Directory and Office 365 portal usernames.

Here is the rule, when you use hyphens or periods you can have it in the username, but you can't have it at the beginning or the ending of the username.

Check out the video on how username conventions and what I like to use.

Common username conventions creating users for Azure Active Directory and office 365 portal