The XV-Z15000 is a bit thin in terms of warranty! It comes standard with a one year parts and labor warranty, which is less than the average 1080p home theater projector.
There are a few others with only one year, including the Panasonic PT-AE3000 (but Panasonic often offers a 2nd year as a mail in rebate). BenQ's W5000 also has one year (a very direct competitor). That said, most home theater projectors come with two years of coverage, and there are definitely more 1080p projectors offering three year warranties than those offering only one.
Also a number of projectors offer anywhere from one to three year replacement program (many are one year, and they are never longer than the warranty). If you have a projector with a replacement program, the manufacturer will simply send you a replacement unit (typically not a new projector), if yours has a warranty issue. The replacement normally goes out before you have to send your projector in. Those programs mean minimum downtime, with the replacement projector arriving within a couple of days, as opposed to however long it would take the manufacturer to repair the projector and send it back. The Sharp does not offer a replacement program.
Bottom line: Not a great warranty. Because of the cost of projectors and that repairs tend to be expensive, I normally recommend buying (at least) a 1 year third party extended warranty, if the manufacturer doesn't sell one. In other words, I recommend that people have at least two years coverage. Of course manufacturer warranties tend to be less problematic than 3rd party coverage, but, it is still a good idea with this Sharp projector.