I thought weapons were repaired when using bonfires, never looked too much into weapon durability though, could be something added later.
It may be weird but I've gotten used to never looking at a weapon's stats, I just look in the status page to see if the total damage is better than what I have, if it's not then I ignore it.
I always skip Blighttown, master key FTW! Only time I went through it all was when trying to get the plat as there are a couple of things you need for it there and it was not fun, like the worst parts of the Valley of Defilement from Demon's Souls fused into one hellish nightmare.