Refining General Skills

Each general in Evony can have up to four skills. Typically you want to train historical generals, who have 1 special (pinned) skill, and three others (skill book) you can select yourself.

Tricky part comes from the way how skill books are added to generals: second skill of your choice will have 50% chance of replacing skill you already have added, and third skill of your choice - 75% chance of wasting valuable skill book. 

There is one exception here - if you already have lower level skill, higher level skill book will always upgrade existing one.

Level 3 (gold) and level 4 (red) tiles are rare, and hard to get. Hence there is a chance of wasting lots of these valuable artifacts.

New general with single special skill. We want to add three skills above. There are plenty of level 1 skill books for those three skills in worst case skills would replace each other number of times.

Solution for this is simple:

1. Make sure to use level 1 skill books first. It is important to have an extra ones as skills often replace previously added ones.
   
2. When all 3–4 skills are set up at level 1 you can upgrade them to higher level of the same skill, they will always replace lower level skill books without risk of replacing something else.

Fully set up skill palette of a general, ready for upgrades. In this case we spent 4 level 1 tiles to set up 3 different skills. Lucky case.

Using prepared skill setup above, we can upgrade one of level 1 skills to level 3 when new skill is obtained. The same can be done with other two skills, when higher level skills are obtained later without risk of wasting this level 3 upgrade.