I want to start opening those chests, exclusively with lockpicks.
Which one should I open, and with which ones I should not even bother?
Is it good to open any chest in EotN?
Is it good to open any chest in hard mode?
I don't need advanced guide, im not going to do chest runs. I only want to know which chests I should open while normally playing the game, without wasting my lockpicks on trash.
Chests question
Servant of Kali
ShadowofWar
Its good to open most any chest with lockpicks.
In normal mode, you have a much higher chance of retention and therefore lucky points [not to mention if said chest was "high end" like in the later part of the campaigns and it drops a gold at which point your happy to get a treasure hunter wisdom and lucky point]
Now opening locked chests in Hard mode.... you must be wary for the broken lockpick purple drop looms around every corner... it can make even the most manly men cry. almost forgot the good side....
anyway higher chance for "good" items by that I mean not to shabby mods and what not. Also still treasure hunter and wisdom titles for gold item drops. Oh and not to mention a good chance for some unlucky points.
Helpful? ^^
In normal mode, you have a much higher chance of retention and therefore lucky points [not to mention if said chest was "high end" like in the later part of the campaigns and it drops a gold at which point your happy to get a treasure hunter wisdom and lucky point]
Now opening locked chests in Hard mode.... you must be wary for the broken lockpick purple drop looms around every corner... it can make even the most manly men cry. almost forgot the good side....
anyway higher chance for "good" items by that I mean not to shabby mods and what not. Also still treasure hunter and wisdom titles for gold item drops. Oh and not to mention a good chance for some unlucky points. Helpful? ^^
Maccarelly
I think it depends on whether you want to commit to long term lockpickage or short term.
Long term : Open every chest you find, this should increase your ranks in treasure hunter and lucky and therefore increase your retention rates. Check wiki for when lockpicks become more effective than keys in their respective areas.
Short term : Short term lockpicks aren't really effective. It will be more effective to buy the keys for the area, the key price will correspond to how high end the items are likely to be ie obs keys = chances at decent stuff ascalonian keys = toy soldier items. Only real reason to use keys short term is if you are too lazy to buy lockpicks and have excess amounts of money.
So if your in it for titles/long term gain use lockpicks on everything, if you only want the fun of opening a chest once in a while go with the key of the area.
Long term : Open every chest you find, this should increase your ranks in treasure hunter and lucky and therefore increase your retention rates. Check wiki for when lockpicks become more effective than keys in their respective areas.
Short term : Short term lockpicks aren't really effective. It will be more effective to buy the keys for the area, the key price will correspond to how high end the items are likely to be ie obs keys = chances at decent stuff ascalonian keys = toy soldier items. Only real reason to use keys short term is if you are too lazy to buy lockpicks and have excess amounts of money.
So if your in it for titles/long term gain use lockpicks on everything, if you only want the fun of opening a chest once in a while go with the key of the area.
Servant of Kali
Meh i opened 3 Vabbi chests 3x with lockpicks.. 47% chance of not breaking and... they all broke! 
..but i guess in the long run it should be about 47%, not 0% 
Purple drops so far, but I'll see if some items are useful on my heroes.
..but i guess in the long run it should be about 47%, not 0% Purple drops so far, but I'll see if some items are useful on my heroes.
Titine
Is it good to open any chest in EotN?
In NM i would say yes. However in HM EotN chest do not drop elite tomes, which gives me a lot of money back to buy additional lockpicks. EotN is harder to run too because of monster skills like KD from giants or centaurs.
Is it good to open any chest in hard mode?
I would prefer faction and nf chests. You can get nice skins and elite Rt tomes in faction, nice skins and inscribable items in NF.
And if you want to max Unlucky title, fastest way is to open chests that have nearly 50% retain rate and cheapest way is to open chests with highest retain rate.
In NM i would say yes. However in HM EotN chest do not drop elite tomes, which gives me a lot of money back to buy additional lockpicks. EotN is harder to run too because of monster skills like KD from giants or centaurs.
Is it good to open any chest in hard mode?
I would prefer faction and nf chests. You can get nice skins and elite Rt tomes in faction, nice skins and inscribable items in NF.
And if you want to max Unlucky title, fastest way is to open chests that have nearly 50% retain rate and cheapest way is to open chests with highest retain rate.
Sethellington
When using picks you'll also be raising Lucky/Unlucky titles at the same time. If this is something that doesn't interest you then gw wiki's Treasure Hunter page has tables of where you break even using lockpicks vs. keys depending on your treasure hunter / lucky level.