I noticed the Owner's manual for my B2710 says the hydraulic strainer doesn't need to be cleaned until 300 hours, but the service manual says it should be cleaned at 50. Seems kind of lame that they can't get the two manuals to agree. Fortunately I never noticed what the service manual said, so I just cleaned it at 170 hours and I couldn't tell it had ever been used it was so clean. So for anyone worried about this sort of thing, I'd say don't bother with it until 300 hours.