The Ultimate Toolkit: 20 Must-Have Tools for Every Electrician
7. Circuit Testers: Safety First

You never want to guess whether a circuit is live or dead, and that's where circuit testers come into play. A combination of touch and touchless testers should be part of your toolkit.
The non-touch circuit tester helps you measure magnetic draw to indicate whether a line is live, while the touch tester will check the voltage range of a line to confirm it's within safe limits.