On Friday, I sent 13 emails and received about 40. 10 of those 13 were responses to others. Many of these were planning meetings or events where faster responses meant more got done today. This was not particularly unusual for a weekday. A couple of these were ones where we proceeded to have a conversation. I am a college student, but I am the leader of a couple groups on campus and heavily involved in a few more.

In my case, where about 1/4th of the emails I get need a response, I would say my current method of having a small pop-up come when I get an email works pretty well.

The once a day method works for people who don't need to respond, or response time is less important. But that's not true for everyone.