As I had failed finding an app that was not ad-ridden or oldish, my girlfriend and I are using this (I am copying her values, to know when her period will be).
Also contributing some code :)
Using anything except some kind of active measures to avoid pregnancy doesn't pass my engineer brain and certainly doesn't pass my wife's Pharmacologist brain (i.e. she actually knows what she's talking about whereas I'm using applied probability theory with assumptions).
A strip confirming you’re ovulating is pretty useless by itself if your partner is on the other side of the country.
Honestly just for fun? I think girl stuff is cool and my partner indulges me. It does truly help with emotional/sexual/physical planning, but a very biological embodied flavor of fun is my real reason.
It's that or there are people who actually think that counting days is a good way to enable unprotected sex without a risk of baby. Which is absolutely isn't - it changes the risk to 2-5% a shot. Compared to around ~2% year for condoms alone.
* For myself, I find that the Americans who try to force everyone else to follow their personal positions to be insane Authoritarian Fascists. Our society only works if people have freedom and personal choice.
I/we track it, mostly because she is a bit clumsy and forgets when her last period was & when the next one is. So not for ovulation tracking at all. Once she told me she thought she was pregnant because her period still was not there; I checked chats & the app and could confirm her period was still two weeks away :).