In NZ we can carry a min of 60mins fuel to a destination, which includes the instrument app fuel, provided. The weather forecast at destination is above 1000ft over the inst app minima and the vis is 5km or greater, and the destination has 2 parallel runways.
Should we be forced into landing with less than 30 minutes fuel remaining, then an emergency must be declared.
THe policy works OK, but does require an increased vigilance by the crew. However most places we go to have somewhere on the way that we could duck into for more fuel if required.