Troy Hunt runs an outstanding free online service at https://haveibeenpwned.com/
In short, you register your email address on the website, and the service will notify you when your email address has been compromised in a data breach. His description of the latest breach applies to me as well:
Pwned again. Damn. That’s me who’s pwned again because my personal data has just turned up in yet another incident from a source I can’t attribute. Less than 3 weeks ago I wrote about The Unattributable “db8151dd” Data Breach which, after posting that blog post and a sample of my own data, the community quickly attributed to Covve. My hope is that this blog post helps myself and the 69 million other people in this one work out who collected and then exposed their personal information.The Unattributable “Lead Hunter” Data Breach
Realistically, if you use the internet, your data will almost certainly be compromised in the future. You might as well find out when it happens.
In this case, I learned the following: