Agree with PD and Penguin. I did 7cm, and it was pretty tough (the whole process, that is).
I'm honestly super, SUPER lucky that I was able to work from home for about 4 months after I finished lengthening (which in itself took 3.5 months, including a month of pre-training). I was even luckier that I got paid my whole salary the entire time doing it. If I had to start working right after lengthening, I would have been royally screwed, because my walking was atrocious. My walking honestly didn't even begin look normal again until about a year post-op, and even then, my gait was still off (I'd say it took two years post-op to have perfect walking again and pretty good running/jogging).
I feel like a lot of the older diaries on here (and the old forum) really downplay how long the recovery process is. I still haven't taken my rods out, and I honestly just might leave them in, because they really don't bother me. I know it's not ideal, but I honestly don't want to have to deal with more surgery, scarring, recovery time (although less), etc.
I think people need to exercise extreme caution and planning when going beyond 6cm in one segment/procedure.