You would have to do a lot of posting and receiving of emails to go over the limit.  I have had the same 2 emails accounts (hotmail.com and mail.com) for years one is my junk/news letters etc one and the other is my personal hotmail just increased the normal size of the inbox and as it was I have only used a small fraction and I dont delete as often as I should and I had over 75 pages of emails  when you would think that it would be full it still have a huge amount open.   If you are worried just make sure that you delete any unwanted emails right away.