Item Durability

So back in November I read about a fun idea on the Tao of D&D, discussing item breakage. In my mind, D&D could certainly use a little more caution and preparation, as if the players put in lots of time and effort to be equipped to achieve their goals, their goals will feel sweeter once they are achieved. So to insert a bit of tension and fun/stress (a little stress is exciting after all), I developed a program as Alexis suggests in the linked post.

It's an Excel file which requires macros and VBA and such, along with iterative manual calculations. Also, it's generally very ill-advised to download Excel files off the Internet which have built-in macros as there are a whole host of security issues you risk exposing yourself to. So if you don't feel comfortable then don't download it.

Here's the basic appearance of the generator:

It works very simply. You first tell it whether you want to generate a new item or not. The generator then, using the specified material and quality of the item, along with whether or not the item is magical, generates a number which corresponds to the total "resistance" in days of that item, along with helpfully informing you of the item's stress tolerance.

Once the total resistance has been generated, you tell the sheet not to generate a new item any more and recalculate.

As you can see, the generator has produced a number of "Stress Taken," again in terms of days. This represents how, over the course of one day of use, the item has fared. It is understood that, were the item to be placed in a vault constantly and regularly cleaned and maintained, the stress taken would be 1. The number instead generated represents the stress of regular use on the item, which is hence larger.

The "Break Chance" beside "Stress Taken" shows the chance the item will now break on a d100. It is calculated using a cumulative exponential distribution function where x is the stress taken and lambda is the inverse total resistance. This function means that the item's break chance should be around 66% once it reaches its total resistance, so the item can actually survive past the total resistance date. The reason "Break Chance" exists is that sometimes, though the item shouldn't break for a long time, it does anyway, perhaps due to a fracture in the material or a freak accident. Maybe the character is just really clumsy.

Right now, that chance is 0%, so there's no need to roll. But let's say that the next day comes around, and the character carrying this poor iron item - say an old dagger - also falls off a parapet forty feet above the ground. Now the character takes fall damage, and so does the item.

The character took 15 damage from the fall, which was also added to the item (the item also took another 5 stress damage during the day, bringing us up to 23). As the total resistance is quite high, there still is no chance of breaking.

Let's say the character then enters a dungeon, falls into a 20-foot pit and spends 3 days fighting troglodytes to get back to the entrance. Here's how the dagger has held up:

It has now taken 47 stress and has a break chance of 2%, so at the end of the day, the character will also need to roll a d100 to see if the item breaks. 

100 days pass and the item takes a bit more of a beating:

Now it has a 22% chance to break! Yikes! It's only made it 105 days from when the character first received it.

Anyways, that concludes a brief intro of the generator. Here is a link for those interested in using it. I will try posting a more detailed version of it later, which also includes a basic character sheet.

https://drive.google.com/file/d/0Bw6d7rcFKzN4b0x4U3RCWFhfYTA/view?usp=sharing

I may make a few edits to the file as time goes on.