Bietrume is right.
I have put about 10K on my Strida 5.0 (with Schlumpf 2 speed added) riding daily to work. Always run the belt slack and adjust the snubber gap as Mark suggests.
HOWEVER - I have gone through the OEM plastic pulley in 0.8K, and 3 aluminium pulleys lasting only about 3K each. This renders the Strida into the toy category for the daily commute. Belts always fail about the same time, due to the knife-edged pulley chewing them up.
Contrast that with my previous belt experience on a Japanese Bridgestone Lacrosse full size bike. After 10K, driving to work on exactly the same route, the belt was original and the rear pulley original and no perceptible wear on either. The 3 main differences from the Strida were:
-Automatic belt tensioner (patented) inside the crank wheel. No snubbers here. Belt as slack as you like.
-Steel rear pulley, not plastic (!) or aluminum.
-12" height for pulley above road dirt, vs. 6" for Strida.