Used Wheel Slow Spin
 

I just got some lightly used(at least they appear that way) 2006 Mavic Ksyrium Elites. They are true, and the hubs/bearings feel smooth when I spin the wheels. My only concern is that when I spin the front wheel, it seems to stop quicker than all of my other wheels. Like I said, it feels completly smooth, it just doesn't spin for that long.
Ride without worry or go straight to LBS?

LBS.

Or better, learn to pack the bearings and do the adjustment yourself.

Is the combination of rim/tire/spokes lighter than your other wheels?

If so, then that could be what allows it to slow down before your other wheels.

You probably need a hub adjustment (loosening the abit)

yeah, less rotating mass = less inertia when you spin it = spins shorter amount of time. I have the same wheels and noticed this as well.

But then again, it wouldn't hurt to make sure it is in adjustment.

The elites are lighter than the wheels that came off the bike. I am going to the LBS before I ride them. I don't trust myself with any bearing related adjustments. Thanks!

If there is no side to side play in the axle, and they sping smooth, the bearings are most likely adjusted just fine.