Picking a basic lock isn’t much of a challenge if you have a little training, decent tools and all the time in the world.
What can make it hard is when you don’t have the time you need or your tools aren’t great.
Each attempt at pick a lock takes 10 seconds.
A lock pick in a rush can reduce this time by taking a penalty of -1 to their skill for each second they cut from their attempt.
However taking one's time and being more careful greatly increases the chances of success, a lock pick may opt to make one check every 30 seconds in exchange for a +1 bonus to their skill check.
A lock has two qualities that come together to make the experience more dynamic and interesting, as well as more realistic.
The Two primary aspects of how challenging a lock is to pick are Difficulty and Complexity.
The Difficulty is generally related to how sturdy the construction, how tight the key hole is, and if there are any security measures included in the locking mechanism meant to foil thieves. The difficulty can also be modified by the quality of your tools. A “Standard” pick set doesn’t modify the roll, but makes it possible to pick the lock at all. Master work tools, or enchanted picks may add bonuses, where improvised or crude tools will impose significant penalties.
The Complexity indicates the number of successes necessary to open a lock; this represents the number of pin and how complex the mechanism is.
A Poor lock might have a base Difficulty modifier of 0 and a Complexity of 3
An Average Lock might have a base Difficulty modifier of -2 and a Complexity of 5
A Good Lock might have a Difficulty base modifier of -5 and a Complexity of 8
An Excellent lock might have a base Difficulty modifier of -8 and a Complexity of 12
Exotic locks might be easier but require more successes, really sturdy locks might be harder but require fewer successes
Pay attention to your Degree of Success or Failure on each attempt as how well you do or how poorly will change the result as follows:
On a success:
Increase your successes by 1, when your number of successes is equal to the Complexity of the lock you pick it.
For each 3 by which you surpass your skill check you earn an additional pick.
Roll of 3 or 4 = add an additional +1 successes on top of the other successes earned by this attempt.
For Example: If Jake has a Lockpicking skill of 15 and he's tyring to pick an Average Lock with standard tools he needs to roll a 13 or less on his skill check. Jake rolls a 10! Because 10 is 4 less than 13 his attempt earns him 2 successes. A roll of 13 would earn him 1 success where as a roll of 7 would earn him 3 successes.
Failure doesn’t automatically mean the end though. Unless something goes terribly wrong or there's a security measure in place failing to pick a lock does nothing but waist time.
A failure of < 5 simply means you make no progress towards opening the lock.
A failure of 5+ means you lose all progress and need to start over.
A roll of 17-18 means you've damaged the lock (and possibly your tools) in a fundamental way! The damaged lock can no longer be unlocked, even with the proper key/combination.