How many frets for classical music?

[CHASAX]

Recall having to use a very high fret on the A string of a mandola playing a mandola part.
How many frets are best for a mandolin for classical music?

[Beanzy]

Well 26 gets you up to an f# which can pop up in some of the Calace pieces, but I wonder if they were writing for the fretboard rather than a real musical need when people like him did that kind of thing. More expensive 'Soloist' mandolins were often defined by having extended fretboards along with more trimmings. Of course if one maker has one with 21 frets the what's the next one going to do to make his 'better' in the peacock tail world of orchestral pecking orders?, yep there'll be one with 29 frets before long.
I went for 24 on the e and a courses when I commissioned one, as that's a nice logical two octaves & even on the longer scale arch top things just get too small for my chubby fingers towards there. If I need anything past there I figure I can just fret with the fingernail anyway which is more accurate for me even from about 21 up.

[JeffD]

How many frets? All of them.

[Rick Schneider]

My Embergher 5bis has 29 frets, as does my La Bottega del Mandolino Magistrale

[Tavy]

It's worth mentioning that too many frets can get in the way of the pick, yes you can adjust, but IMO it's somewhat questionable just how musical the instrument is above about fret 17 frankly. That said less than 20-22 might not be enough, more than 24 is likely to interfere with your pick, and most instruments are in that sort of range.

[Beanzy]

This is embarassing, I just counted mine and checked the email of my final spec and I have 26 I can only assume I was feeling inadequate at the time and trying to compensate or something

[crisscross]

Builders of modern German bowlbacks make the distinction between "Orchestra Model" and "Soloist Model".
The Orchestra models have 20 or 21 frets and no fretboard extension, while the Soloist Models have 24 to 27 frets.
I'm completely happy with the 20 frets my Jacob Orchestra model offers me.
My Suzuki has 24 half tone and the 2 whole tone frets. But as Tavy mentions, these frets get in the way of the pick...

[DavidKOS]

Well 26 gets you up to an f# which can pop up in some of the Calace pieces,.

the Soloist Models have 24 to 27 frets.
.

Some of the solo pieces need the high G.

I say 27 frets is the minimum. 29 would be better for covering violin solo literature.

However, most of the music I play does not need those notes. I will use them if they are there, though!

[HonketyHank]

I swear I saw one o them Eye-talyan jobbies with frets clear down to the tailpiece.

[Eugene]

All told, very few virtuoso showpieces extend beyond 24. 17 or 20 was pretty standard to typical "Golden Era" Neapolitan mandolins, again, with "soloist" models up to 24 or 29. I have a few instruments fretted to 24 or 29 (de Santis, Favilla, and a Lyon & Healy archtop), but extend into the 20+ range only on occasional pieces. Unless you're planning to dabble in the virtuosic stuff by mandolin specialist composers, 20 would likely suffice in almost all other situations.