Prototyping saves weeks of development on ideas that don't work. The key is matching fidelity to the question you're answering.
Low-Fi Wireframes
Gray boxes and placeholder text. Use for layout and information architecture discussions. Fast to create, easy to change.
Mid-Fi Prototypes
Real content, basic interactivity. Test user flows and navigation. Tools: Figma, Balsamiq, pen and paper.
High-Fi Prototypes
Pixel-perfect with real interactions. Use for stakeholder buy-in and developer handoff. Don't skip straight here.