If you start to use a simple to-do list once a day, your productivity will increase 27% on average even if you do nothing else differently. This is regardless of if you use an app, a spreadsheet, or a written piece of paper. That’s how powerful having a written to-do list is.

Often when I ask people if they have a to-do list, they respond, “Yeah, my email is my to-do list.”

Um, no.

Using your email inbox as your to-do list is a terrible idea. Let us count the ways:

1. It focuses you into busy-work mode or firefighting mode, not in a “getting important things done” mode. The entire problem with email is that it constantly calls to you, whether or not it’s a good idea to spend your time there. Most people spend time checking, reading, and responding to email when they should be getting very important things done; things they may never get an email about.

Most of your big, important, new projects to grow your business will not generate any email to your inbox from external sources, at least not at first. You must generate these task items. That means your own separate to-do list.

2. It’s very hard to prioritize tasks if they’re all sitting in your inbox. Priority is a critical time management function. None of us have enough time in the day to get all of our work done. This means we must focus on high priority tasks first, moderate priory tasks second, and perhaps scrap all other tasks.

When there’s a pile of email in your inbox (or other folder you’ve created), it’s just a giant “wall” of various tasks. You can sort email by date received or person, but there’s rarely a way to sort by priority, which is what you need.

Even if you do respond to email by priority, that requires you to run down your list of email, likely several times, to figure out which are priority items and which are not. With a simple to-do list, you don’t have to waste your time doing this; the list is already sorted correctly by priority.

3. It’s too chaotic. While responding to emails, you often get new emails coming in. Then what do you do? Pause and check them, right? Hard to control yourself to not do this, right? Right.

That’s another problem with email. New crap is constantly flowing in, screaming for attention, and often getting it. It disrupts your workflow.

When I’m banging out items from my to-do list, my email apps are all closed. That includes my phone, by the way (I always have email notifications disabled there). No one bothers me. I’m 100% focused. And I get a lot done.

I’m sure some of the more techy nerds out there will come up with solutions to some of these problems, like creating a priority folder system or regularly disabling the send/receive function whenever you’re working in your email app, but that doesn’t solve all the problems, and more importantly, you don’t have to do any of this stuff with a normal to-do list.