I've not got particularly long fingers - they're best described as short and stubby! But I have no difficulty covering five frets, even at the 'wide fret' end of the neck. My main guitar is a Yamaha FG160, circa 1970, and I use medium gauge strings.

A stretching excercise I use with pupils is to start around the 9th fret, put the index finger of the fretting hand on the 6th string (9th fret), second finger on the fifth at the 10th, third on the fourth at the 11th and fourth on the third at the 12th.

Once you can make all the four strings sound 'clean' - no buzzes - move down (pitch - away from the instrument's body... 1-6-8, 2-5-9, 3-4-10, 4-3-11), and keep going until you can't hold all the notes without a buzz.

The next step, once you can get all the way to the first fret, is to only move one finger at a time - that's a killer!

The sequence is:

1-6-9, 2-5-10, 3-4-11, 4-3-12 all held simultaneously,
1-6-8, 2-5-10, 3-4-11, 4-3-12
1-6-8, 2-5-9, 3-4-11, 4-3-12
1-6-8, 2-5-9, 3-4-10, 4-3-12
1-6-8, 2-5-9, 3-4-10, 4-3-11
1-6-7, 2-5-9, 3-4-10, 4-3-11 and so on!