I've got two iPads, a pro 9.7 and a mini 4, two iPhones, a 6S+ and a 6S, plus a Mac and iTunes to update. Two of us, but I do it all. I'm being made redundant at the end of November so I'll do them gradually either in December or January. I can't deal with any issues while I'm still at work.
I'm not naive enough to think at least one device won't muck up, which means iTunes has to be done first