Are Lamm preamps hard on tubes?

I have a LP2 and an LL2.1 (purchased about 14 months ago) and my system is missing some of the sparkle lately. I'm wondering if the tubes (all purchased as NOS from Brent Jessee) could be wearing out? That would seem awfully quick for 6922 and 12AU7s right? Not sure about the 417As in the LP2. Any thoughts for anyone's experience with Lamm?