That's a judgement call on the part of the Captain in consultation with his F/O(s) and dispatcher.

The problem is that nobody knows how long the delay will be and often it's quicker to go refuel sooner, being one of the first to do so, than waiting longer then being at the end of a long line waiting for a fuel truck.

It also depends on how much extra fuel you had to start with. Sometimes you have a good bit of extra while others it is less due to the particulars of the flight and the weather conditions enroute and at your destination.