The further we go in this journey, the more we learn and can then "optimize" but hindsight is certainly 20/20. There is plenty I learned as I cycled that I wish I knew when I started (e.g. not all clinics are good for DOR, pay for meds OOP to not burn through lifetime max, etc). That said, if you've done 8 rounds (not sure if those are retrievals/transfers, but even if both that's a handful) and it's not working then I'd look to change things up too. Some do this just because, some do it because they want to see different results..and some stay because it's a numbers game and hopefully it works out eventually.
but, if you're running into same issue over and over (e.g. seeing drop-off with embryo development at day 3 or 5, not fertilizing, etc) and your doctors haven't addressed, then you should definitely look elsewhere. Your numbers (AMH, FSH etc) are good to know but ultimately it's your retrieval results that are most telling, and most informative for next steps. I never tracked things meticulously and purposely stayed laid back, but by the time by 3rd retrieval failed I took the reins and made changes to increase my chances of success (changed clinics, advocated for certain protocols over others, etc).