knowing your limits and understanding the challenges that you're dealing w/ are probably the most important thing when it comes to safety. If a hiker is wondering how to ford a stream recommending loose, heavy, water-logged boots may not be the safest option.
But I am curios to hear why you stopped carrying sandals
How many rolled/sprained ankles and sticks through the foot do you have to get before you use something that actually protects the foot better? If you cannot find a place to wade, or a tree to walk across, and you cannot see the bottom of the creek, you have to feel your way or abandon the trip. If you are search and rescue, you don't abandon the trip.