The benefits of using expendable email addresses for most things
One of the big email things that I do as an anti-spam and anti-annoyance precaution is that I basically never give places my real email address. Whenever something demands an email address in order for me to sign up, I make up an expendable address for the purpose (I know, I'm lucky that I have convenient access to as many expendable addresses as I want through a local facility that's sort of for this). All of the expendable addresses wind up in my real inbox, but I can tell which address an incoming email message came in through.
The lesser reason for doing this is that you'll pretty much know who leaked one of your addresses to spammers or other sources of unwanted email. Pragmatically this isn't good for very much except perhaps stopping doing business with the place involved; these days, places that leak addresses generally don't care and aren't going to change their ways just because you can demonstrate it was them.
(Note that leaks don't necessarily have to be deliberate, and some things leak almost by the nature of their existence. For example, bug trackers often expose your email address and mailing lists intrinsically leak your address to other subscribers (if you send email to them) and may leak them through publicly visible archives.)
The big reason for doing this is that you can turn off expendable addresses in a way that you can't with your real email address. Tired of 'unsubscribe' options that don't really work? Unsubscribe yourself by deleting the expendable address involved. Done. The lesser version, suitable for places you want to keep interacting with, is to make up a new expendable address, change your address in their system to this new address, and delete the old address. Everyone with the old address and no access to the new one is now out of luck.
What all of this does for me is not necessarily less spam but instead peace of mind. I can give out email addresses without being so stressed about it and I feel much more in control of my email because by and large I get to decide if people can keep emailing me, not them. On the whole this helps to stem or at least slow down a general retreat from email.
As a side note, modern email clients make it relatively convenient to interact with people through expendable email addresses. They support multiple sending addresses, they're often smart about picking the one to use on replies, and at least sometimes you can configure rules about which one should be chosen when. You don't really need client support if you're just receiving email through the various addresses but it does come in handy if and when you want to interact with people through them just to be sure.
(Because I use some old-fashioned tools for my email, I don't quite get this convenience and there are some obstacles in the way of it in general.)