Naah! Why carry another bit of electronic crap around. If you have a smartphone, there's a neat app available called ClearTune, which works really well and allows very accurate tuning.

And while on the subject, why do so many performers at folk nights and open-mic nights stick their tuner on the end of the guitar and bloody well leave it there all night and NEVER tune at all?

These days I use the phone app, but I do actually have a tuner, which I would put on beforehand, tune and then put it back in the case.

Surely anyone playing before an audience can handle any minor tuning issues during your set by ear? If you can't, you shouldn't be playing in public anyway.

But to have an unsightly tuner sticking out of the end of the guitar - never used - is just laziness and a sign of a lack of confidence.