So this is going to be long because I want to make sure all the info is in here.

I got a box of 10 opk’s. This is my first month using them. I’m on 4 mo. Ttc. I am averaging a 28 day cycle and on my projected ovulation date (based on multiple apps) I always get some sort of ovulation cramp and after that I get ewcm. Since it’s only a 10 pack I feel like I should know when I need to start testing. This is the last month that I will be able to do this as my job/ my SO job requires a lot of travel the first few months of the new year. I would love to bring in 2019 with a bfp so PLEASE help me! Any tips/tricks/signs, and most importantly WHEN should I start testing?! THANK YOU!!!