Two or even three email accounts will assist in keeping your inbox clean and tidy. One or two emails should be used for personal / professional use. Another email used for purchasing, registration subscriptions etc.
When we buy online our data is recorded. Some of these suppliers will keep it safe however, as you have probably noticed, most will not. Selling your email address is one of the main problems. Using an email only for purchasing or registering on web sites will then keep your primary email addresses free of unsolicited SPAM email.