Greg,

I come from the school of thought which teaches that an electronic tuner helps the student reject bad pitch by conditioning the ear over time to hear the differences between actual and perceived pitch. Rather than becoming a crutch, the tuner quickly and easily provides a means by which the student can tune accurately at home and at their lessons. There's no sense in tuning a guitar to a piano which might itself be out of tune. Tuning a guitar to itself is wonderful until one discovers that between lessons it has been driven sharp or flat. We used to solve this by using a tuning fork (I still use one when I'm travelling) but lately these seem to be falling into disuse.

At the beginning of each lesson I have every student tune with a tuner. Minor tweaking throughout the lesson will be done by ear unless there is a problem with intonation, machine heads, or some other mitigating factor. Simply dropping to drop D would be a job for the ear for example. I try to set an example by retuning by ear, having students compare pitch, and so on.

When I started playing, I tuned badly with a pitch pipe, but within a few months I could tune quickly and accurately by ear. Observing my tuner equiped students I would say they catch on just as quick.

Certainly for beginners with little or no prior music discipline a tuner will get them over that first most daunting hurdle. A well tuned guitar is much more likely to be well played.

Beware that depending on a guitar's intonation, some minor compromises may be necessary between the pitch of open and fretted strings, particularly on cheap and poorly maintained instruments. Otherwise tuning the open strings for open position playing is usually sufficient.

Hope this helps.

Peace, Mooh.