For the most part I use 1/4 inch hardware cloth behind the grill. But I put it on as soon as I buy a new truck or new to me. Whether I am going to Alaska or not. Lots of road debris on the Interstates, etc. on my current Chevy, I put a commercial, attach with Velcro, bug screen on the outside.
It works well and no over heating problems. Keeps the bugs out of my radiator and oil coolers. Several spring times I have found myself in places with cottonwood trees, putting off their fuzz. Looks like snow in the air and will clog a radiator fast. The way they stack coolers in the front makes it difficult to keep them clean without some type of protection.
I keep a small whisp broom under my driver's seat and will brush off the screen several times a day, such as when fueling, etc. a few trips back, we got into swarms of bees in northern BC and southern Yukon. I was very happy I had a screen on the front. It may have stopped a few rocks here and there as well.
On a couple of rigs I have installed one of the plastic, raised bug deflectors on the front or the hood. Mixed feelings on them. At highway speeds, the windshield washer fluid goes everywhere, due to the disrupted air flow, but after a trip or two, the rock cracks and chips in the plastic of the bug deflector, told me it was working on low flying debris. Don't use them anymore.
On Alaska trips,
In 2006, I chipped a windshield in Iowa, on the Interstate and about 2009, I broke a windshield, just out of Valdez, due to meeting a loaded gravel dump truck, that was running without a load cover. Nice paved road, but nothing would have protected me from that blast of gravel. Just had the glass replaced when I got home. Florida requires full glass coverage.