I had 5 stim cycles, 3 FETs and 7 transfers (1 X 1 embryo, the rest 2 embryos transfers) and had a successful singleton pregnancy and birth on the 8th cycle.

Before starting IVF, it seemed to me too that everything you read or hear about is how people fell pg first time, but the truth is quite far from that. In fact you only have around a one in 5 chance of success for each transfer (on average, as different types of transfers have different success rates). And those chances don't improve at each cycle, they stay the same, and it's only the law of averages that say you might likely be pg by the 5th cycle. But like throwing a dice, you just never can tell how long it'll take for your number to come up.

So I reckon that if you have it in you, do persevere. But everyone only knows in themselves when enough is enough.