Ooh, I was about to suggest this! I loved the skill challenges in the journal! Every skill had a set of challenges and rewards. Here is the challenges and rewards for Handiness from Sims 3 for example:
Handiness
Electrician
Electricians have repaired at least 10 electrical objects. The experience gained means they will never be electrocuted by an electrical object again.
Plumber
Plumbers have repaired at least 10 plumbing objects. They are so good at repairs that plumbing objects repaired by them never break again.
Tinkerer
Tinkerers have finished at least 10 unique upgrades on household items. Installing the "Unbreakable" upgrade on multiple objects only counts as one unique upgrade, so it helps to experiment with different upgrade options! Tinkerers never fail when upgrading objects.
