Lamp life, regardless of projector manufacturer, is a crap shoot. Take the hours that the projector manufacturer advertises and cut it in half. Now, having said that, I've seen lamps last longer than they were supposed to but I've also seen some fail much earlier than expected.
Also, lamps dim as they age and you can expect that a lamp will have lost at least 75% - 85% of its rated output by the time it fails. Of course, you will probably find the quality of the image unacceptable long before that.
And don't try and save money by buying generic or so-called "compatible" lamps, they usually aren't and there is no shortage of reports in these forums who bought those aftermarket lamps and wasted their money.