If you have been trying to conceive for more than a year (or more than six months, if you're over 35), and you have not succeeded, it's time to see a doctor. Some couples decide this advice isn't really for them, though. It's for those other people, you know, the infertile ones. They decide to keep trying on their own and pray for a miracle.
Here's the problem with that thinking: There are some causes of infertility that worsen with time. While you pray for your miracle, your chances may be quickly disappearing. There's nothing wrong with deciding to keep trying and wait on treatment, but you shouldn't avoid fertility testing. Go get checked out, both you and your partner, and confirm that whatever is wrong can wait. Then, if you want, set a "miracle waiting" period. Speak to your doctor about how long they think you can try without losing valuable time.