I would inspect for wear of drag link and tie rod when you service the truck and of course at your annual inspection.
Simply, have another person turn steering wheel back and forth and watch for movement at your drag link joints and tie rod ends. Shouldn't take more than one minute. If you get to point where you start to see movement, then change it. If you are checking every couple months at services it would be plenty sufficient to catch wear before it would be unsafe. If inspecting when you do a service, inspect for movement before you grease the joints.
In the rust belt often tie rods are getting changed because they are rusty in the threads and aren't able to rotated to adjust the toe of the steer axle, rather than being worn out at the the joints. I am coming from more a mechanic's perspective and would curious what truck owners experience has been.
Keep them greased and there’s no time limit. I had one go bad on a Truck I bought at 500k. Just replaced the original on my current Truck @ 2.5 mil. Original King Pins and Tie rod ends are still good. Check all that, including steering u joint at steering box and inside cab. They used to go bad on me. I found that the newer sealed ones without a grease fitting last much longer, surprisingly. Might as well check spring bushings. Wheel end play. That just about covers everything. One bad part tends to put extra wear on the others.