I used this with FL4K for instance, to quickly switch from a pet tree I wasn’t liking, and then I loved the next one I tried. This allows you to play around with your skill points however you want.
This is kind of a general Borderlands advice thing, but I think many new players may not realize that A) they can respec and B) they can respec for very, very cheap, less than it costs to die and respawn or refill your ammo. Don’t miss your loot in this hidden part of the menu. Sometimes they’re bad, but I got many rares and epics that I ended up using immediately because they actually drop at your level, which can take some time in the wild. There you will find email that has not just story tidbits sometime, but literally every level you will be mailed a gun. Rather, it’s in the “Social” part of the other menu that you would normally use to pause or quit the game. But it’s not a terminal on your ship, it’s not anywhere in the inventory menu.
When you level up, you will constantly be told that you are getting “email” that you need to check. This one was so confusing I actually had to email Gearbox about it during my review process.
