Momentum hates unnecessary resets.

Every stop and restart costs more than the time it appears to take, because beginning again requires reassembling the context, the materials, and your own frame of mind. A week of interruption can wipe out a month of accumulated ease, which is why unnecessary breaks are more expensive than they seem while you are taking them.

When something is running well, protect it from the small interruptions you would normally accept without thought. Move the appointment, decline the trip, keep the thread alive with a token amount on the difficult days. Continuity is worth more than intensity here.