[Mini-Guide] Mabinogi Repair % System Is a Lie?

• Jahrakal wrote on 2010-05-11 02:51
  %The backbone of this guide was originally posted on the Nexon Official Forum%
  
  %English is not my first language, I apologize in advance for grammar/spelling errors%
  
  
  
  How often have you failed your repairs and said "OMG MABI REPAIR RATES ARE BULL****!"
  
  This is a mini-guide for people who are curious about the repairing mechanics in the world of Mabinogi.
  
  [SIZE="5"]Repair Success Rates - Oblivious Facts Behind Repairing Mechanics[/SIZE]
  
  Even at 98% success rate, you still fail sometimes a few times in a row. This is not % system's fault, but your lack of knowledge on how probability works.
  
  Here's a simple example to aid you with basic concept of how repair rates work. In this example, I'll discuss 95% repair rate.
  
  
  Think of a box full of 100 golf balls. 5 of these golf balls are defective (let's call these red balls).
  
  

  
  
  1. What are the odds of getting a red ball when you randomly pull one of the golf balls out from the box? 5/100.
     
  2. What are the odds of getting a golf ball? 95/100, hence, the repair rate.
     

Even with 98%, eventually (with replacements), you will pick a red ball at least once in the long run. Sometimes you get un/lucky (depends on how you want to look at it), you get another red ball after your first pick. Note that 5/100 is only 1/20, so out of 20 tries, on average, you will fail once.

It feels like you are losing out a lot simply because the number 95% and 98% look promising to the eyes. I am willing to bet that you do not remember exactly how many times you succeeded repairing since you started playing, but you roughly do remember how many times you have failed the repairs.

If one was to write out a chart of success/failure from one specific NPC since he first started playing, the average will be close to the repair rate of that NPC.


[SIZE="4"]Difference Between Perfect Repairs and Point-by-Point Repairs.[/SIZE]

If you do perfect repair (meaning attempting to repair all points at once), your success rate drops dramatically, resulting in almost a guaranteed failure. This is why a lot of players use point-by-point repairs.

Example:

Let's say you're trying to repair 0/10 dagger, blessed/non-blessed is irrelevant for this discussion.

If you do point-by-point, your repair sequences and rates are like this.

• 98% -> 98% -> 98% ->.... -> 98% -> 98%
  

If you choose perfect repair, it looks more like this.

• (98% 98% 98% ... 98% 98%)
  

On perfect repairs, the system overlaps the subsequent repair rate followed by the first attempt.


For easier understanding:

[98%] -> [98% of 98%] -> [98% of 98% of 98%] -> .... -> [98% of 98% of 98% of... 98%]

Each arrow representing each point in durability when you're using perfect repair.

See the problem here? The chances decrease the more durability loss you have. Therefore, items with 0/5 durability have way higher success rate than the ones with 0/30 durability, using the perfect repair.

Example: At 98% repair, using perfect repairs

Dura : Success Rate
0/1 : 98% chance to fully repair (This is the same as point-by-point repairs)

0/5 : 90% chance to fully repair
0/10 : 81% chance to fully repair
0/15 : 74% chance to fully repair
0/20 : 67% chance to fully repair
0/25 : 60% chance to fully repair
0/30 : 55% chance to fully repair


Following is an analogy irrelevant to probability, but explanation of the concept of why the rates are like that:

Think of 30 cars trying to park in 30 different spots all lined up side by side all at once. - Perfect Repair
Think of 30 cars lining up in 1 line to fill up 30 spots 1-by-1. - Point by Point


To sum it up, if you attempt perfect repairs at low durability, you are pretty much guaranteed to fail a point.

I will not mention the effects of Holy Water and rainy days, as they have very little to do with my topic.

Cheers.