My clycles are fairly regular, but my cousin experiences irregular cycles. She told me to me have sex 365 days a year as a sure way to get pregnant. Funny enough, she has 5 kids! So she knows what she's talking about.
I had very irregular cycles (long would have been ok, but I could never know how many days to expect...33 or 53) until baby#1 apparently straightened me out! I never used opks due to the extra cost involved...I'm cheap :) but I did start charting, taking my temps in the morning & paying attention to cervical mucus...made a lot of difference for me, and made it possible to get pregnant...without quite as much worry, wondering, and stress.
Mine were very irregular due to having pcos. I am now pregnant with my 2nd child. Start using ovulation kits. If you have long cycles, try to find the biggest packs or look online. They can be expensive. I didn't like the clear blue easy digital tests (with the smiley face for positive). I got false positives. Good luck!
My cycles were irregular and made trying to conceive difficult. One month a cycle could be 14 days, the next one 54 days. Try an ovulation tester. Take one every day until it shows ovulation. Then have sex that day and again three days later. We bought our home and moved so we were going to wait one more cycle to start the ovulation tests. But instead, we conceived. It isby impossible, just takes a bit more trying: )