Just did a 5,000 mile drain. Can was half full. Over the 5,000 miles it was daily driven 45 miles a day in moderate traffic (morning and after work rush hour) and highway cruising.
The catch can is capturing a good amount of blow by; there was also soot/sludge build up on the bottom of the can.
So far 12,000+ miles with the catch can and all is holding up well and working like it should.
Those of you that have gotten the catch can kit from me, I hope you're catching a good amount of oil.