I wouldnt say they a essential for everyone, but I love them!
I have two different kinds, the cheapys which I use about 3-4 a day when the line start getting darker.. and when I get a + on a cheap opk I then use my Clearblue Ovulation digital tests to confirm that its a + ..Love seeing that smile


and like
samy23 said it gives you notice on when your going to O, and I dont have tons of EWCM so thats a good thing for me, and i just like backing up my temps

I also take them until my temp jumps as well to confirm O or I take them til there really - but thats just me!