I noticed I know only two or three other bears who change their gear before the boss. I do that nearly in every run, to change from an higher armor setup for mobs to something more appropriate for a fast boss kill.

So for example in hideout runs, I start with an 8-armor ring, talon and shield, giving me a decent 122 armor and nice dodge.
But before facing Goldfinger I switch to recurve and bravery ring. This way I only got 86 armor, but killing the boss seems faster with the higher damage.

So how about you other bears, do you switch depending on who you want to kill?