Ultimately, it depends on how many hours the engine is operating.

If you only use the truck to go hunting, and it sits without ever being started the rest of the year, you're probably fine changing it at the end of hunting season, just as you park it for the year.

If you're a contractor using the truck as a base for radios, gen-sets and other such uses, only driving the truck from job to job, but allowing it to run for several hours a day, you likely will need to change your oil far more often than twice a year. Probably more like once a month.

Also, the dirtier the environment the engine runs in, the more often the oil will need to be changed.