I got tired of the wrong ammo being equip when I would run out of arrows and having to open my inventory to change arrows. Not only that but I didn't want to clutter my favourites menu with arrows and bolts. Thus I created a script based ammo switcher. You can use any two keys you want to cycle through the ammo. With other options like excluding spears when cycling through bow ammo. It doesn't stop spears from every being equip, but you can cycle past them quickly if Skyrim decides to equip them for you.
Looks neat. I like simple UI mods like this, it can make the game that much more enjoyable to play.