How do you stop "got a quick sec?" messages from ruining your entire workday?

I used to respond to every Slack tap or shoulder tap instantly thinking it was just part of being responsive.

After tracking it for a week I realized every "two-minute question" actually cost me 15 minutes of context switching and broken focus.

Moving to dedicated check-in windows twice a day completely saved my deep work time, and surprisingly nobody complained about the slight delay. How do you protect your focus hours from endless ad-hoc interruptions?