Yeah, this is more often used to upgrade armor

Very unlikely, yes. Like the other person said, this ability if for armor mostly, and occasionally melee weapons, but it’s also nice for thrown weapons.

Thrown weapons gain triple durability each time they’re upgraded, and if it reaches 100 uses, it becomes infinite. So a weapon like the Large Boomerang, which has 15 uses, becomes 45 uses at +1 and 135 uses at +2 (infinite).

So if you are lucky enough to find three boomerangs before you reach the Troll Blacksmith—or even just two–consider reforging them. A +2 boomerang hits for a lot of damage, and comes back after a couple turns. It’s better than most low level wands. It also doesn’t get stuck in enemies so it’s hard to lose track of. (I sometimes stick throwables into enemies, then have to run away and they wander off and I lose track of the throwables.)

No, but it’s not common either. Always hang on to duplicates if you haven’t been to the blacksmith yet.

unlikely but sometimes I hold off on the blacksmith until after I’ve been to the dwarven city and found two items I can combine, like the ring from the imp. also i sometimes try transmuting a wand and wind up with two crappy identical ones. I just combine them at the smithy, and wait for another transmute scroll. lots of possible minute variations.