Years ago I came across Mailwasher and used the free version but decided to buy the full version last year. A year later they wanted $30 a year to keep it activated so I told them to stuff it. I only have one major email account anyway.
The change meant that I would no longer have an audible/visible indication that an email had arrived. As soon as ‘ding’ is heard, you have to stop what you’re doing and open the mail, just in case – and it was interrupting the day. Now, I have made a policy only to open mail in the morning. None is that urgent anyway and it frees up the rest of the day for continuous work (or continuous loafing).