I'll give you some help. Save your money by never purchasing it again. There is no need for regular bacteria "updates" In a healthy tank, where would the bacteria go? If a bacteria dies, a new bacteria grows to replace it. Unless you let your bacteria die off by depriving them of food (taking the fish out), or letting the filter dry out, or dumping antibacterial medicines in the tank, the bacteria will be fine. If extra bacteria were added, they would just starve anyway. The colony that exists in there as it is, has grown to the size it has corresponding with the number and size of the fish in the tank. Specifically, the colony has grown large enough so that the colony's rate of consumption is exactly the same as the rate of production from the fish. So, any extra bacteria would just starve anyway. So, there is no point in adding bacteria that will do nothing except starve. That doesn't even open up the debate about whether that is the right species of bacteria in the bottle anyway, and how it could remain alive without access to food or oxygen. If that was too subtle for you, the points in the last sentence are also valid questions to raise concerning this product.
So, I just wouldn't ever buy such a pretty much useless product ever again. Don't feel bad, it is in the LFS's and company's best interest to sell you stuff, so they make it sound like these products are really useful and necessary. Consider it a small lesson in not always trusting the LFS.