Surprisingly,the other day I heard that planes do not necesarily refuel at each airport they land (specially small planes like DC-9, 727, 737, A320, etc). It seems that some time they are loaded with fuel and fly two or three times without refuelling in each airport they visit.
For example I heard this on a flight from Madrid to Barcelona and then to Geneve, the plane did not refuel in Barcelona! (a pretty big airport). For your knowledge the plane was an Iberia MD-87.
I though this was a highly expensive procedure since if you fly with a lot of fuel you don´t need you are flying with a lot of extra weight that will raise considerably your fuel compsumtion.
Is this a rare procedure or is it usual? If it is usual, what's the reason for so?