When to start OPKs???

Theresa • Married for 3 years, Cat Mom of 10 and an all cat Veterinarian, TTC baby #1 for over 1 year..... ♥️♥️

Hi ladies.. I am currently on CD7 and on my 3rd day of Clomid 100mg, taking it CD 5 to 9... This is my 3rd round of Clomid... I was wondering what day should I start OPK testing ??? I feel like last month I started way too early and it threw me off... any advice is appreciated!!!! Xoxo