In most labs, you are a slave. I have a lot of scientists in my family, and none of them stayed in research and all of them were very glad to get past the graduate student and post-doc stage.If you are a non-student lab technician, then you have found yourself in a lab where everyone is dedicated to the task at hand, and those getting a degree can see the light at the end of the tunnel. You as a non-student employee though could potentially be there for a LONG time, and not taking time off is unacceptable.Either find another job, or just take the time off anyway and deal with any repercussions later. Make sure your work is STELLAR though and your interactions with post docs and the one in charge are STELLAR, because if the one who runs the lab wants to terminate you because you took earned vacation, you could sue for wrongful termination. They have to show cause. They could probably get around it though by "restructuring" their lab and eliminate your position, hiring someone later or bringing in another grad student, so if you decide to take vacations anyway, be prepared to have to find another job.