IUI - opinions?

Need some opinions from you ladies. Next month, we’re going to start Letrozole + IUI.

For background, my husband has excellent count and motility, and low fragmentation. So he’s clear. I have been cleared of inflammation issues like endometriosis. FSH is below 10. But my left tube is blocked. My egg count is on the low side for my age, but not low enough to prevent pregnancy.

We tried on our own for four months with no luck. Last month we did a natural but monitored cycle (to confirm ovulation from my open side) and no luck. Because I’m going to be 36 later this year and my count is on the low side, our doctor recommended Letrozole + IUI. We are totally in agreement to take this next step.

My main question - and I’m curious of your thoughts/experiences - is how many cycles is reasonable to consider before moving on to IVF? Given we’re largely in the “unexplained” category, it’s hard to jump to IVF right away. That said, with my age and count (I’m something like a 0.95 AMH - doctor says for my age they want to see more like a 1.2) we certainly don’t want to waste months and months of time and money on IUI should we need to move to IVF down the road.

Thoughts? Be open to try 2-4 IUI and then move on? Less / more? Curious of your experiences. Thanks!