1. Insurance — preferably errors and omissions — and a license

2. An up-to-date computer, preferably a laptop

3. A Web site

4. Professional business cards and brochures

5. A reliable vehicle of neutral-color and unremarkable appearance

6. Office space with secure storage for client and target information, and equipped with a computer, printer, and shredder

7. A low-lux video camcorder with image stabilization, zoom lens, and auto control

8. A variety of tripods

9. Communication equipment, radios, and a good cell phone

10. A wearable or portable covert camera