Age
From Toadwater Guide
Your dwarf begins at 10 dwarven years old and ages 1 dwarven day per standard hour. So your dwarf ages 24 dwarven days per standard day. More importantly your dwarf ages 1 dwarven year every ~15.2 standard days -- this is important because each time your dwarf ages a dwarven year, his skills also automatically increase. Some players call this the age bonus.
- Years 1-79 add 1 per year to every skill.
- Years 80-120 add 0.5 per year to every skill.
- Years past 120 add 0.1 per year to every skill.
Your dwarf's current age is in the info center.
Age can also be used to refer to the age of a tree, which changes how much it heals and the yield from cutting it down.