I have pretty much settled in on the mini T3 as my regular clearo. So now I am starting to stock up on heads. I am still cleaning my original ones and reusing them but just cracked opened a brand new one last night. Yeah quite a difference. But don't want to toss the old ones until I am sure they are completely dead. Just wondering what you guys do to keep track of your heads. The older ones vs the newer ones. Looking for ideas.