I've been keeping my horses barefoot for about 5 years now. My Mustang (who was kept in shoes by his last owner) does awesome on nearly any terrain. In any of my rides off the property, he goes barefoot and never has any issues. He has only had a stone bruise (slight lameness in one front foot after a ride where we did a lot of cantering) ONE time in 5 years. So I think that's a pretty good record.
I do carry Easyboot Epics and often use them if we trailer out, just because there are a lot of trails with lava rock around here, which are really sharp on the feet, and because I never know what kind of trail we will end up on, I feel better carrying the boots and using them (only on the front feet) if I feel we are riding in a super rocky area.
Now my Fox Trotter mare, whom I have only owned for a little over a year, I will definitely carry and use boots on this summer (again, only the front feet seem to need it) because she hasn't been barefoot as long as the Mustang and seems to have more sensitive feet. But she has been doing really well so far this spring.
My feelings are, that if you don't ride in the rocks much and your horse can get away with riding totally barefoot, just do it! If your horse has trouble in the rocks, you will know it, and you can buy a pair of boots just for the fronts. I have had boots last a couple of years, so they are worth the money. You just have to replace worn hardware occasionally. I have had best luck with the Epics. The Gloves don't fit my horse's round hoof shape at all. I know Epics have basically the same shape, but perfect fit doesn't seem as important as the cables hold the boots on even if they aren't a perfect fit.
I have heard a rumor that Easycare will have a new boot for wide hooves at some point, but I don't know that for sure. It's kind of funny, because wide hooves are healthy hooves, but you can only find boots to fit contracted or oval feet. Strange, huh? Oh, we tried the original shape Old Macs, which are made for wider feet, but they started cracking after 2-3 rides. (Easycare was kind enough to exchange them for Epics since the Old Macs where brand new). Now I stick with the Epics. I've never had one crack, just eventually they wear thin after a couple years of hard use.
PS. I have ridden for as much as 5-6 hours on the trails with my horse totally barefoot. I don't think time/distance is an issue. It's more about the terrain and how well adjusted your horse's feet are to traveling on it. But you will know if your horse is sensitive and needs extra protection. If he doesn't, then just go barefoot. And if not, get a pair of boots, they last a good long time. :)