I have 68000 on my engine. Still run dino, as the extra costis incurred and savings arent realized since I change it every 3000. Not to mention that the benefits for synthetic would not actually be a benefit for my case. YMMV.
Could I go longer? certainly, but with the amount of off highway travel my rig does, and the fine gritty sand we have around here, I choose not to. Thusly, I change it and run dino, and see no issues with it.
Another thought on the break in treatment on the engine...
Drive it like you ordinarily would. I have experienced and seen seals go bad and things of that nature when babying the engine at first and then driving aggressively later in its life.
That school of thought was fine back in the day, but with the higher engineering tolerances, compression, and well designed engines... I see no reason for failure from driving like you ordinarily would.
Take care,
Keith
Do not meddle in the affairs of dragons for you are crunchy and taste good with ketchup.