I make heavy use of email scheduling (and more recently Slack message scheduling) and will often schedule messages to go out in a few hours or the next day. That way, I can get my thoughts down in the moment, but not get sucked into a back-and-forth when I don't have time for it. I work with students and have found that delaying my responses tends set their expectation that they're not going to get a quick answer and train them over time to spend a bit more time trying to find an answer themselves because they can't depend on me for an immediate response.