I always found that left-handers who played 'standard' way around did significantly better than my right-handed pupils - and Segovia was left handed, too.

The guitar seems to favour left handed people, so there should be no need to reverse the instrument unless the pupil has already started playing 'the wrong way round'!

I've heard lots of arguments to the contrary, but I've yet to be convinced... after all, you don't turn a piano around... and you use both hands equally to play guitar. Yes, people argue that strumming 'feels more natural' to a left hander when the instrument is reversed, but I argue that a guitar doesn't feel natural until you've learned to play it, and strumming isn't exactly the most important consideration!

I'll concede that maybe a fiddle, because of the bowing arm, may need reversing, but then, that's not my field of expertise.

It's also worth remembering that a left handed instrument tends to cost more than a right handed one.