Although lots of musicians post reviews saying gStrings and some other tuner apps are accurate, I have wondered if it’s worth purchasing a dedicated tuner. Are you thinking of something like the Korg TM50BK, Melodica-Me? Or are we talking about something much more expensive?
It is clear to me that I am able to significantly improve the tuning of my melodicas using gStrings Tuner, and I believe the same would be true even if I were simply tuning by ear with a tuning fork or from my electric keyboard or recently tuned Yamaha piano. I’m a real duffer on guitar, but it’s not pointless to tune my own guitar, even if it’s just by ear. So I have to disagree with the judgment that it’s not worth doing your own tuning unless you have state-of-the-art equipment, just as it’s silly to say that it’s not worth playing an instrument unless you’re a professional.