General Considerations when setting-up eMail
There are many eMail programs and setups and I have no wish to detail or describe them here. This page relates to configurations that I currently use and maintain.
I primarily used Gmail for my mail servers but I also administer a number of domains that can support their own eMail and mailboxes. These can be used with other eMail programs/platforms such as Google, Yahoo and BT. The email can be forwarded and/or used with Gmail.
My personal email is just a forwarding of my email addresses to Gmail and I do not use a mailbox on my domain servers. However, there are reasons why you may wish to use a "hosted" email service with Gmail.
Having said that, there are still situations where mailboxes get full and have to be emptied.