It happens to the best of us!
About a week after getting my Kubota, I decided to build a lean-to behind my shed in order to shelter the tractor. I no sooner had the frame up and braced nice and square when I drove the tractor under for the night. Well, the ROPS hit the header and totally racked the whole frame out of whack. I guess I am lucky I made that mistake early, before I poured concrete around the posts and had finished building the whole thing. What's dumb is that there wasn't a roof on it at that point, so driving under for the night was more of a ceremonial formality with no benefit anyhow!
After that, I hung some ribbons from the header as a reminder, and I usually keep the rops at 3/4 height by default, only raising it when I go off to do a project. Hopefully, this is one mistake I won't repeat!
At our next place, I will build a proper barn with a door that is high enough to make the ROPS a non-issue. Actually, I'll make it even higher than needed to idiot-proof any future tractor upgrades as well. If anyone asks why my doors are so tall, I'll say it's because I'm an idiot and leave it at that....