My Korg rack mount tuner is 17 years old and it works very well.
Paid about $150 for it I believe. I've spent $0 on batteries for it.
That's pretty amazing if you can do that and be perfectly in tune with other musicians or a recording. I have a pretty decent ear, but there is no way in hell I would trust myself to do that in a performance situation. Plus there are usually a few other people trying to tune at the same time, and a drummer randomly hitting stuff for god knows what reason.I tune to E by first humming Day Tripper.
Dead serious.