Good question...
about the number of other accounts to administer. I have five that are different business accounts of hosted web domains. Then there is my Yahoo / ISP account, plus the two 'ghost' Yahoo accounts. Including Outlook.com, I'm now up to nine different email accounts. Where does it all end???
(later that night) I did max out the number of sent from addresses at five. Not really enough, especially if I wanted to add on a 'regular' work address.