Do I need new wheel studs or bolts when I install this?

Check your studs during install — if they're intact and threads are clean, reuse them. Most Prius hubs are fine with existing hardware if nothing is damaged.

Will this work with my factory brake rotors, or do I need new ones?

Rotors are separate — inspect them while you're in there. If they're smooth and within thickness specs, keep them. If they're scored or worn thin, replace them at the same time to avoid noise and poor braking feel.

How long does a wheel bearing usually last on a Prius?

Depends on driving — lots of city stop-and-go means more bearing work. Get 80,000 to 120,000 miles typically before hearing noise or feeling play at the wheel. Listen for grinding or humming when turning; that's your signal it's time.