The vast majority of services use email address to identify you so diversifying your email addresses helps a lot. I've known about every hack/info leak ahead of

The vast majority of services use email address to identify you so diversifying your email addresses helps a lot. I've known about every hack/info leak ahead of everyone else for that reason - I use a unique email for every service. I also use different cards for the major online retailers / tech giants so knowing the last four digits from my Amazon account is useless to validate anything else (though this does require having several credit cards or debit cards). Whois privacy is absolutely required. Unfortunately if someone is determined enough, almost all ISPs, cell companies, retailers, etc will happily give them control of your entire digital life. You can only minimize the risk somewhat.