boondocking is no different than many other life experiences. There are both positives & negatives, but for most of us the positives far outweigh the negatives.
How you know if boondocking is allowed, somewhat depends on where you are, what country, what area of the country, out in the woods or near the city. Here in the US on all Federal lands, both National Forests and BLM, boondocking is allowed unless there are signs prohibiting it.
How long you stay in one place varies a lot, and how you deal with the water & waste varies a lot depending on your situation. Many fulltime RV'ers, long term travelers or retirees in RV's may stay in the same boondocking spot for months. Many others are short term travelers who's stay will be only a few days. Many of the public lands limit your dispersed camping to 14 days in the same spot, so sometimes you change sites just to comply with that 14 day limit. Obviously the month long stay will deal with water & waste different than the ones only staying out a few days. As a long term boondocker I had the choice of either taking my rig to a nearby dump station every 2 weeks, or draning my tank into a "blue boy" and hauling that to the closest dump and bringing back drinking water in 5 gal jugs to replenish my tanks. If I was boondocking while traveling from point A to B, I would just dump and refill the tanks as I moved on down the road.
Yes there are wild animals out in the wild areas where we boondock. Very rarely do those wild animals attack adults, but I have seen & heard of hungry coyotes occasionally snacking on a small dog or cat. In the SW desert at certain times of the year our western diamondback rattle snakes will strike at both humans and pets who cross their path.
Safety in the wilds is not much different than safety in the city, you have to use some common sense, but bad things can happen anywhere. Just as with choosing where to park your car or where to go walking in the big city; you should be comfortable with where you choose to camp and take basic precautions. If your surroundings don't feel right, move. I've never felt threatened out in the woods, even when I walked up on a black bear on the hiking trail. But I frequently get uneasy walking or driving through sections of a big city.
So my version of the truth is that I can't imagine being a happy RV'er without a big dose of wilderness boondocking. It takes some planning, preperation and learning from experience. But well worth the effort.