For the person who only has two sets....I am not sure how much or how long your menses are. But you may want to start using them now. I go through a lot more then that a cycle. I need several each cycle. I have about 14 and they don't last my whole cycle, I need to buy at least another 7. I have been using them for a year though and love them. But, I have found I had to tweak them too. Like double the core, and such as that to work better. So I would start using them now to make sure you got the right fit, and right core etc etc. I bought mine off etsy, and as I have figured things out that I like and dislike about them, I ask the seller to change the next batch she makes me accordingly.