I have had the mirena iud in for almost 4 years. I am not looking forward to having it taken out(no periods,no birth control worries)--but i think 5 years is the max. I had it put in at my six month check-up,after having my second child. I had had an IUD about ten years ago. (before having children-which doctors usually advise against)I dont remember exactly how long I left that in(a couple of years), but for the first few months i had terrible cramping in my legs(my sister also had one put in around the same time--she quickly had hers removed because of the cramping) I, however persivered---and eventually the cramps went away. When I first had this one(mirena)put in--I FULLY expected cramping--but I didnt get any. I thought it must be because i had given birth 2x, and everything was"stretched out" or something to that effect! Anyway-I have had no problems, and do NOT look forward to worrying about getting pregnant(YUK!)and I do NOT look forward getting my period again. I have not had it almost 5 years!!!(9mos.pregnant, breastfeeding kept it from returning before the IUD insertion- I did that for 18 months. I do not miss it. I also used to get wicked PMS! no-more period-no-more pms! I hope that doesnt return! Maybe its just not for everyone!