I set a vibrating fitness tracker to go off every 25 minutes to prompt a micro-break, but started using it as a fake 'urgent call' excuse to leave bloated brainstorming sessions. (The guilt peaked when a colleague asked if my phone needed exorcising, but my calendar has never been so clear.)
I told myself I'd only work on it for five minutes (which always turns into longer) and suddenly, it didn't seem so overwhelming anymore.