I was wondering, how often does it happen to "run out of fretboard" like Tommy Emmanuel (almost) does in this video around 0:30 ? Do you ever feel limited by the range of the guitar while improvising ?
I "run out of fretboard" very frequently on guitar, but not while improvising, and not at the high end. When writing, I often wish I could play lower on the guitar.
I also play piano/keyboards and bass, and I like to be able to have a good low-end as a foundation in music that I write. On piano I can have it all, more or less, but even then I don't spend a lot of time playing the highest octaves on piano, but I do play down in the lowest octaves frequently.
Most of the time, I don't much care for the sound of the very highest notes on a guitar, so I'm not motivated to go above the 15th or 17th fret on the high E string in most cases.
To avoid running out of fretboard it is useful to be comfortable with a number of different scales and know how to play "beyond fret 0" when doing scales focused on a barre chord position/chord shape.
But then practising scales is not a popular occupation...
I run out of fretboard frequently when I play solos on my acoustic guitar because I want to play very high pitches at points in the solo.