Below is a photo of my OPKS the cycle I got pregnant. I was testing every morning. But as you can see, I went from low to high in one day. And I went from high to PEAK within the same day. If it’s high in the morning , sometimes is helpful to test 12 hours later so you don’t miss your peak. If I had waited 24 hours and tested the next morning, I would have missed my peak. Remember that once you ovulate, your egg is only available for 24 hours.