I never paid a whole lot of attention to how much scent I use, just always used a good bit though. On my drag rag I just keep adding scent to it about every 15-20 yds to my stand, I just freshen it up with a couple drops. I can honestly say that I hardly use a drag rag though, just because the scent weakens as you get close to your stand. The deer will usually follow the scent to where it is stronger and that is usually where you first started using the scent drag. To your question I dont think you can over use scent. Just dont get carried away. I usually go through about 3-4 bottles of scent a year.