~~258~~ I, myself, have a CI and have had it for 3 years now. Although these days, I don't wear it on a daily basis due to the nature of work I do. ( I work as a Carer in a group home and I wear a body processor with a cord connected to the body processor to the coil near my ear -- it is constantly grabbed by clients at work and getting pulled off.)
-- for those who opt for a CI -- choose a BTE not the body processor, heh.
Besides that...before I had the operation, I had to go through a few assessments to see if I was a CI candidate: balance check (some operations on the ear can severely challenge the sense of balance), listening test (got about 47% accurate), and audiologist test (75% and 85 to 90%). When the operation came up, I opted for the worse ear which was 85 to 90% severely/moderate deaf as I didn't have much to lose.
About a year after surgery and hook up, my listening skills went up from 47% to 71%. I reckon that has slid a bit as I don't wear it on a daily basis these days.