Your e-mail box is 50 (MB) megabytes and the average email messages size is 20KB so you are looking at around 2500 messages before your mail box is full. However if you are sending pictures, documents, and PDF's (acrobat files) or receiving those then your email message sizes will drastically increase and your box will fill up much faster. Your mailbox will also fill up faster if the e-mails you are sending and receiving are more then just text; if they have pictures or links to the internet in them that takes up more space as well but not as much. When your box fills up, you stop receiving mail. What we recommend that all of our clients do is setup their e-mail account in Microsoft Outlook and then so long as you download your mail on a semi-regular basis (dependant upon your usages and file size) then you will not ever have to worry about your mail box filling up.