OPK's and CM

This month I was testing and got no smiley...nothing (I did stop testing at CD16 due to a terrible cold), but then noticed what a HUGE change my CM had made(on CD19) so we BD on those 3 days. (CD19, CD20, CD21).

I am noticing lately that everyone is going by when they "O' with either getting a smiley or two lines.
So here is my question...everywhere I have read...CM is the BIG clue that you are about to "O". Am I reading this correct?

As always...thanks in advance for all the wonderful advice you ladies give.

Re: OPK's and CM

CM can vary throughout your cycle.

Was it EWCM that you saw at that time?

EWCM isn't a great way to pinpoint when you O. Some people get it 2-3 days before O... but I get it 5 days before I O. So if you are like me, then you would have wanted to continue the BD marathon for at least 3 more days...

OPKs help you narrow your O date down to 2 days - so that's why people like to use those.

Re: OPK's and CM

Thanks! It was EWCM, then changed to clear and stretchy for 2 days then clear and not stretchy.
It's all hit or miss for me I guess. It amazes how so many people get a "one shot" deal and the rest of us are spending half the day POAS!