Editing Comprehensive guide to potion making (section)

=== A little math excursion ===
To determine when to start making a certain potion (or item in general) is difficult because of the stochastical nature of failures and successes. An in-depth discussion can be found in the [[Guides/Probability|probability]] guide.

For making potions you will have to include the price and break rate of mortar & pestle in your calculations, which comes down to 0.33 gc (100 gc cost, 1 in 300 chance to break) per attempted mix.

Ideally you don't fail and you don't lose ingredients, so your cost in making an item is the sum of the prices of the ingredients, the price for the food to make one item and the tool price per item (0.33 gc). However that's not reality, so you'll have to calculate with failures both critical and non-critical and you have to keep in mind the price that NPCs sell the items for, which might make making some potions unprofitable for you; while the fact that NPCs buy some potions will make some potions very profitable for you as well as set a lower bound for what you should charge players.
With that said you will find, using the tools of the probability guide, that some potions will be profitable for you even if you loose half of your ingredients while others will never be profitable.