Old Smokey stated it best concerning take off flap settings. Short runways usually require more flaps and climb restrictions on hot and high altitude airports especially require minimum flaps. These are calculated on losing an engine at V1 and either stopping or continuing when using normal balanced field length V speeds at the take off weight. Sometimes using more flaps makes sense if a high speed abort would put you at more risk such as wet runway or a cliff at the end of a fairly short runway and climb is not critical.