Adding my two cents worth(True Story)After tuning by ear for 70 years I thought I was an expert.I was invited to join a group for a jam and was expecting a night of enjoyment.I tuned my guitar to the piano by ear and headed off to the jam.When we started playing before the first tune was over one of the musician said your guitar is out of tune so I handed it to one of the musicians and he screwed around with it for a while handed it to another and another mind you all of this by ear and when I got it back in my opinion it was really out of tune.Needless to say my evening was ruined.The next day I went to the music store and bought agood tuner for $60.00 and I made up my mind then and there no SOB would ever be able to tell me my guitar was out of tune.Since that day no one has ever mentioned my insturment was out of tune.Yes learn to tune by ear,but also buy a good electronic tuner and a good one will cost you between $60 and 70.