The 75% rule
Advertised flight time is a lab hover; real shooting delivers 70–80% after motion, wind, and temperature taxes — before the landing reserve takes its share. The honest planning number (usable minutes) is what the flight-time calculator computes, and every shoot schedule should be built on it.
The rotation is the real spec
Continuous flying needs (charge time ÷ flight time) + 1 batteries — the number that explains why professionals own five batteries for a three-battery drone. The rotation math also prices field charging: an inverter and a hub turn lunch into a recharge window.
Cold weather is a battery event
Lithium capacity sags 10–20% in cold, voltage sag triggers early warnings, and cold-charging damages cells. Winter drone ops pre-warm batteries (inside pockets), plan shorter flights, and keep spares warm between uses — the conditions multiplier in the calculator is doing real work all winter.