Mechanical

The Sims
The Mechanical skill allows a Sim to repair broken appliances, electronics, sinks, tubs, toilets, and showers at a faster speed which may eliminate the need of a repairman. The skill also reduces the risk of electrocuting themselves when changing light bulbs, however, a maximum level Mechanical skill (10/10) does not eliminate the risk of getting electrocuted. Mechanical skill is also important in the promotion of the Sim's career, including (but not limited to), business, military, science, and law enforcement. In Makin' Magic, a Sim's Mechanical skill affects the number of charges charms they make will have, and how many MagiCoins they'll get for performing on the wooden stage in Magic Town.

To increase Mechanical skill, have your Sim read mechanical books from the bookshelves. In Livin' Large, a Sim can use the woodworking table and make gnomes to increase their Mechanical skill. The higher their Mechanical skill, the faster they make gnomes and the higher the price each gnomes can be sold for. In Makin' Magic, a similar table, the Kraft-a-Gargoyle table is introduced, which also increases the Mechanical skill. In Makin' Magic, Sims can also increase Mechanical skill by using the Prick-Me-Not Spinning Wheel.

The Sims 2
This skill is mainly used to repair things and also in different careers. A Sim's mechanical skill determines the chance of getting electrocuted when attempting to repair a broken object. It can be studied by a book, by repairing broken items or by purchasing the "Jimmy three fingers" rocket bench (console only).

If you have The Sims 2: Free Time installed studying the mechanical skill from a book will increase your sim's enthusiasm for the Tinkering hobby. You also get a broken down car which trains your mechanical skill while you repair it.

The Sims 3
The Mechanical skill will allow a Sim to tinker with objects, repair broken electrical and plumbing objects, and finally, upgrade many household items. The higher the skill the less chance of electricution, breaking, and failing whilst upgrading an object. Like every skill in The Sims 3 it comes with unique challenges to even further your Sims mechanical skill and knowledge. Following is a list of the three mechanical challenges.

Electrician Electricians have repaired at least 10 electrical objects. The eperience gained means they will never be electrocuted by an electrical object again - what insurance!

Plumber Plumbers have repaired at lease 10 plumbing objects. They are so good at repairs that plumbing objects repaired by them never break again.

Tinkerer Tinkerers have finished at lease 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.

Known Upgrades Include: Unbreakable, Self-Cleaning, Improved Crushing, Faster Cooking, Better Graphics, Auto Water, Improve Speakers, Wire House With Speakers, Boost Channels, Improve Meal Quality