One of the safest jobs in the world is that of a piano tuner. If you have enough clients, I would be willing to bet that you can keep your gig and not have to worry about being replaced by a robot. Aside from a downturn in the economy (and a dearth of young people playing the instrument), there isn't much to work against you, as far as I know.
Tuning a piano requires a great deal of skill. And tuning a piano used by people who own the higher end instruments is like being welcomed into a special place. If you own and play a top of the line piano, you're not going to trust it to just anyone. So, when I saw this story about how piano tuners are going to be replaced by robots, I just laughed:
Given that people are picky--and, given that people believe themselves to be able to discern music in ways far superior to machines--I would be willing to bet you that few people will accept the robot tuner unless it is used by their old and faithful piano tuner in order to do the job quicker and cheaper.
But, really. If you're paying someone to tune your piano, what's a few bucks between old friends?