I got my nipples pierced back when I was a freshman in college (so 4 years ago). I took them out 2 years later when I joined the Army ROTC. I got them re-pierced about a year after that. I had to take them out for my FFS (not 100% sure why), but when I was actually conscious enough to put them back in like 4 days later, they were closed. I was thinking about going to a piercer, but decided to let them close permanently. I will not be getting them re-pierced.
Now, to get on topic. The piercing gave my sensitivity a HUGE boost. HRT, boosted that even more. I could have like a nipple orgasm. EPIC!