FYI - many couples track cycles because they are trying to get pregnant.
Yes but as I said in my post - it's not effective. Hormone measuring strips are and they costs very little - $2 / month - and are very effective. We wouldn't have three kids now if we relied on counting days.
You use them in conjunction with each other. For instance, if one of you travels for work, you can try to plan around when you think the next cycle will be.
A strip confirming you’re ovulating is pretty useless by itself if your partner is on the other side of the country.