It is rare I fail to open a chest, I am not alone that have to spend ridiculous time farming rare items.
Prouesse ring took me 2 weeks,
Terminus Earring 2 days, then helped a friend get it, took 3 days.
Liminus earring took me around 6 months of going in & out, not steady farming.
I helped 2 friends get Fishing torque; first got it after 2-3 caskets, second took 3 months of around 4-8 hours farming each day.
Problems is all the crap we can get...
Potions, +1 +2 +3
Hi potions, +1 +2, ether, +1 +2 & so on!
there is around 10% chance of getting a brown casket & then there is around 40-60 items.. not to mention the rare item is most probably 1 to 5% drop rate... that means, without luck this can be terribly long to get. Especially not so fun.
It needs limit on bad luck. Most of rare things in this game needs a limit on how unlucky we can get.