A choice of different ways of tuning

There are many different ways of tuning, depending - for example - whether you're going to play on your own, or with someone else:

- if you're going to play with other instruments, you need to check that your instrument and the others are in tune with one another

- if you play your instrument on its own it's perhaps not nearly as important.

- you might want to tune differently for different kinds of music, e.g. mediaeval, renaissance, modern.

- you might want to take every note from another instrument

- or you might want to rely on yourself & feel that the notes are right amongst themselves.