As all of you know to land without declare emergency fuel we need final reserve at least. On my acft about 2 tons.
Planning with decision point procedure and 2 altn or std fpl and single alternate.
In flight, approaching decision point, manage the altn (if needed) in order to respect the minimum required fuel over the decision point. If impossible to respect the required fuel due to various reason (wx, atc, etc.) divert an refuel.
Til now never happened.
On approach manage altn as above and according the different scenario (reason for any delay, rwys on destn apt, wx, etc.).
Usually land with remaining fuel in a range from 3.5 tons (worst situation) to 5 tons after flights 9 to 14 hrs long.