Hello there! I used an O test (Clear Blue) and found it very helpful as it tells you're going to ovulate 2-3 days before O, so you can get down to business at the perfect time! I was on the pill for quite a long time before TTC and couldn't tell how my body worked, so the test made it easier for me to take control and minimised my anxiety, which is incredibly important when you're TTC. Some people achieve similar results through BBT, but you need to be charting for a long time in order to see a pattern and predict O. Also, the change in temperature only happens after O... a bit late! Same for cervical mucus, position, etc - you need to start 'studying' your body way before TTC. The O test does it all for you and take away the guess work. Best of luck!!!