great test, looking forward to reading this thread. The 2nd day of your test was the scent just as strong as when you started. I'm starting to wonder if I'm just expecting too much from my tarts.. the first few hours they're run you out of the room scent almost the whole house, 8 hours later I'm not smelling them as strong, 48 hours later the scent is there, you can smell it when you enter the house or room but its no longer hit you in the face. Just re-read your post and saw that you said 4 days as strong as when you first burned them. Mine weakens but you can still smell it.. guess I'm not expecting too much. Back to more testing for me,lol