“A socket set or mechanics tool set is a must if you plan to maintain any engine, from your car to a leaf blower. To a mechanic, they are as essential as a hammer and nail are to a carpenter,” says O'Donnell. “Even though a good set can be reasonably expensive, they will last a long time.

Other smaller tools you'll wind up needing in a pinch include circlip pliers, a sharp knife, various-length extension bars, a window removal tool, Torx bits (mandatory if working on European cars), interior-trim pliers and Allen key sets. These can be added over time to avoid a huge initial expense.