Deleting spam immediately helps reduce unwanted emails.
Buying from a spam email potentially compromises a personal computer. A virus, worm, trojan, spyware or ransomware could be embedded into the email causing multiple computer malfunctions as well as security breaches.
Using the unsubscribe option in a spam email only increases unwanted emails as it lets spammers know that the email address is active.
When signing up to newsgroups or other miscellaneous groups, use a disposable email address to decrease unwanted emails from a main email address.
Adding an email address to a personal website invites spammers to use it. Use a web contact form instead to limit spam.
Writing out an email address in full (a at b dot com) helps limit spam emails from reaching a personal inbox. Spambots search for a pattern (firstname.lastname@example.org) in order to attack personal email addresses.