While I am not petroleum scientist, I have had the opportunity to start vehicles that had been in storage for several months with and without STA-BIL. I was easily able to tell the difference. I first started using STA-BIL when I moved to the East Coast, leaving my Ford Explorer behind. The vehicle was in good condition but had 150k miles on the odometer, making me somewhat concerned about starting the vehicle when I returned and/or attempted to sell it. I gave STAB-BIL a try and was very pleased with its performance. In fact, it seems to work longer than the 3-6 months the manufacturer suggests. For nearly two years, I had the vehicle parked in my parents' driveway, much to their chagrin. If I recall, I only put 1-2 bottles in the tank the entire time. I never had a problem starting the vehicle. Ultimately, I was able to sell the Explorer because I had no problems starting and running the vehicle during my brief trips back home.By contrast, a relative has a 1992 Mazda Miata with 35k miles, which is only used in the summer. The owner did not use fuel stabilizer until I purchased it for her. The last time I helped this person get the car started after being stored for four months, it chugged and sputtered for nearly 30 minutes. I would not have felt comfortable driving such a vehicle as it would have been likely to stall. I finally purchased STA-BIL as a stocking stuffer for Christmas '08 and put it into the Miata's gas tank myself. From what I understand, it has worked well. However, the real test will come in Spring 2010. I fairly confident it will work given my experience with my Explorer. Now, I recommend STAB-BIL to family members who are storing lawn and snow removal equipment. Consider STA-BIL a cost effective insurance policy along with simple tips below.Other Storage Tips:Over-inflate the tires to prevent flat spotsStart the car or equipment periodically in the off-seasonGet an AC trickle charge or solar trickle starter for the batteryGet an oil change before storageConsider insect repellants and/or covering air intakes if pests are a problem