Like wares and anebel I don't feed any joint supplements. I experimented for 4 years on supplements with Casey using Gluclosomine, Majestys Flex Wafers (Devils Claw, Yucca) and BL Pellets (Gluclosomine, MSM, Devils Claw, Chodrotrin- sp) with over a year each supplement and no difference. Casey gets a little stiff (vet suspects minor arthritis) in winter.
I ride my horses on all different terrains on trails, clay to rock slabs and occasionally huge step- up rock stairs and don't use boots. First of all, the "worst" (the stairs, rock slabs) terrain I go on is when I am backpacking with my girls.. And riding for 6-8 hours with breaks every so often and going through lots of streams. Boots are not practical. Since it gets quite hot, their legs would overheat and be more prone to tendon injury. So, no to boots on trails.
I jump Candy and don't use boots right now. Why? She is a fantastic jumper over nonscary jumps. Scary jumps, she jumps weird or even stops, and I want her to learn to jump them and actually pay attention to jumping, rather than what she is jumping. So, yay, she learns a lesson when she falls on her face after doing the weirdest jump, because, she learns that maybe next time pay attention to jumping as she felt the pole whack her. At least she was listening and GOING over the jumps! I have open front boots, but, those would only work if she whacked the pole on the front of her cannon. On cross country, yes, I use brushing boots. Those jumps are solid, she cannot trip over them, they are not good learning to jump jumps, so if she whacks her leg, I want protection.
I don't use boots for my low level dressage either. Here is a great article on horse boots. You need an account to The Horse to read it, but if you don't have one, its a great site and I would highly recommend signing up for it. (dont forget, its two pages, click next at bottom of article) The Horse | Researching Horse Boots