Has this ever happened to you?
Someone figured out (broke) the password to your personal email account, and was then able to access your Facebook and online banking accounts. This criminal was able to post to your Facebook wall, transfer money from your checking account, and send phishing emails to your family and friends all because you used this ONE password for all these accounts.
To be more secure online (and avoid this scenario), use multiple accounts for separate purposes. This helps you easily distinguish what type of business is being conducted in each particular account. You can use one account for communicating with friends and relatives, one for all online and offline financial transactions, one for all notifications and newsletters, and one for spam. It is up to you how many accounts to use and for what purpose(s) to use them. In addition, keep your work and/or student account(s) separate from the rest of these accounts.