You know how your inbox fills every day with stuff, much of it unexpected or uninvited? It’s easy to delete it all, but some of it IS good stuff.
The first rule is to set aside specific times when you check your emails. The second rule is to set aside enough time that if you find something interesting you can explore it there and then and make a decision. It means you can avoid waffling, going over the same stuff again and again because you’re not handling it on the spot.
It’s either passing your filter or not. Of course, sometimes bigger things arrive on email that require a lengthy reply, like a request for quote. That’s when you just add it to the to–do list!
Think of email (and many other trivial and recurring tasks) as things that need doing and that must be scheduled in your day, to ensure you don’t let those tasks run away with your schedule and constantly interrupt the important stuff you’re doing.