I close Slack and focus on coding. I take short breaks from coding every 1-2 hours, and check Slack. Replying to someone 2 hours later has never been an issue.

I close Slack and focus on coding. I take short breaks from coding every 1-2 hours, and check Slack. Replying to someone 2 hours later has never been an issue. If it's urgent, people drop by my desk. Definitely don't have slack on my phone, and when Slack is closed, I don't get any kind of notifications. Being able to focus is important. In the end it matters I deliver on the project, not that I reply to every question immediately.