Spottrader:In previous messages I had indicated that I am retired and do not drive as frequently as in the past. I have completed my 3 tank mileage calculation period and put my 2 initial tablets in the tank.At this particular stage I can see that I am well ahead of my normal mileage.I am going on a long driving trip w/in the next 2 weeks and will update my results.As stated before, I passed my 2 year emmissions test with flying colors this week and I am amazed at how much smoother and quieter the engine seems.I am looking forward to completing the 10 tank test in the next 4 weeks, and as of the progress so far,would use these tablets for the engine improvement alone.Hope this helps.At the projected cost of approx. $1.50 per tablet,for me the increased cost was about $.003 per mile---INSIGNIFICANT !!!