I found a great deal on fertility friend VIP membership several months ago, but wasn't ready to start TTC. I put the membership on hold with plans to start using it once trying, and have been charting with a different free app, with plans to switch once I have my paragard removed. How much in advance would you start using fertility friend? Does it need some time to be effective? FWIW, my cycle is regular, 25 days, and I usually ovulate around day 15.