Changing oil based on hours

i have an older pete with cat. Local hauling triaxle dump in harsh conditions we change our oil in 10k mile intervals. I was thinking of changing my oil earlier do to circumstances. Last time I did an oil change was back in October. It was a slow winter. Past 3 months of working everyday and past few weeks 7 days a week 12-14 hour days, still only have 6 thousand miles on the oil change from last November. Truck just sits on high idle most of the time waiting. So it had me thinking, maybe the oil should be changed off of the hour meter. I would like to get as much of this motor as I can. Tell me your thoughts. Should I change the oil before 10k? How many hours? Or does idling, not have to be factored in

 

Thank you for this. So my theory is right then, I shouldn’t be going off miles in extreme conditions and long idle times right?

 

Thank you for this

 

Sounds like so far 250 hours is where these conditions warrant a oil change in my case

 

That’s great another confirmed 250-300 hour range. That looks to be a 359 . I own a 379.