The WD510U has an excellent three year parts and labor warranty on the projector and a one year (or 500 hours, whichever comes first) warranty on the lamp. The lamp warranty in particular deserves praise, as so many manufacturers provide no more than a 90 day warranty for lamps.
The Mitsubishi warranty is one of the very best available. I addition to the three years coverage, Mitsubishi also includes what they call their Express Replacement Assistance program for the full three year period.
If you have any problems or if the projector fails, a toll-free phone call (24 hours a day, 7 days a week) to Mitsubishi will connect you with tech support. If a replacement projector is warranted, it will be shipped to you within 24 hours after warranty verification for overnight, next business day delivery (when and where available). That minimizes down time, and hassle. A great overall warranty and support package!