The thickness of a guitar neck does not make it easier or harder to play per se. It is very subjective and varies greatly, between players, style and thicknesses.
The preference for thickness is likely to be informed as much by the type of neck you learnt to play, and your individual size characteristics, as it is in the neck thickness itself. These issues are explored and explained in detail below.
Answer To Whether Thinner Neck Guitars Are Easier To Play
Thinner guitar necks are not necessarily easier to play than thicker guitar necks. There are many players who find thinner necks easier to play, and many who find thicker necks easier to play.
If you have very small hands, then it can be the case that a thinner neck is easier for you to get your hand around and reach all the strings on the fretboard, but this is not the case for all smaller handed players.
Many smaller handed players still love a big chunky neck to wrap their hands around.
Many thinner necks came about in the 80s to make it easier for ‘shredders’ to move up and down the guitar neck. And though some players do find this case, many other plays says a thin neck gives them cramps if they hold one too long so they need prefer thicker.
The best thing to do is have a play on as many different guitars as you can and see one neck size feels best.
Many people say that their preference for neck size is heavily influenced by the thickness of the neck they learnt to play on, so it is also informed by habit as much as the style you wish to play.
Why Do Some Styles of Guitar Have a Thinner Neck Than Others?
In general, classical guitars tend to have the thickest necks, followed by standard acoustic guitars that have average thickness necks, and then by electric guitars which have thinner necks overall.
Within each of these styles, there is a range of neck thickness available but overall those trends are consistent.
A big reason that classical guitars have thicker necks is due to the fact that legendary classical guitar player Andres Segovia had very large hands with fat fingers and he needed the room.
Given his influence on the classical guitar scene, all the different manufacturers wanted him to play their instrument, as it would have been good marketing, so most manufacturers adopted their style to suit his preferences, in the hope he would play their guitar.
There is also some sense in thick necks for classical guitarists as they require the ability to complex fingerpicking patterns and widespread finger positions, a thick neck can make that easier.
Electric guitars have thinner necks overall, as many find it easier to play lead guitar and ‘shred’ up and down the guitar neck when it is thinner.
But many electric players still look for models with chunky necks as they like a neck they can wrap their hand around, as this provides a source of support rather than having to hold their hand in position the whole time with muscle strength alone.
Are Thinner Guitar Necks Better for Small Hands?
Thinner necks can be easier for people with small hands, as it can make it easier for them to reach all the different strings. But it is not a clear, definite rule.
The best thing for someone with small hands is to go to a guitar store, or play some guitars of friends, to see what they all feel like. The preference for guitar neck thickness is very subjective.
Can I Make My Guitar Neck Thinner?
Yes, it is possible to ‘shave’ your guitar neck. If you know what you are doing you can do it yourself with sandpaper and a lot of patience, or you could take it to a luthier and have it done professionally.
The risk of course though is that it is an irreversible process, so if you go ‘too far’ you can never thicken it. So make sure you go nice and slow.
Understanding the Difference Between Guitar Neck Width and Guitar Neck Depth
A lot of people confuse guitar neck width with guitar neck depth. When we are talking about the thickness of a guitar neck, we are talking about the measure from the top of the fretboard to the back of the neck.
However, when a lot of people talk about thickness, they are something referring to the width of the guitar neck, which is the distance from the bottom of the guitar neck, to the top of the guitar neck.
Neck Shape Should Be Considered As Well As Neck Size
As well as the thickness of a guitar neck, the shape of the neck can have a big impact on how easy it is to play.
This again varies between players, but it is important to keep that in mind as another factor in playability and try out some of the different shapes. The two most common guitar neck profiles are the ‘D’ shape and the ‘C” shape.
As you could guess the D shape has a flatter back with curved sides, whereas the C shape is more of a continuous arc and less of a flat spot.
Again, the key question is not ‘which shape is best?’, but ‘which shape feels best to me?’.
Resources
https://www.ominocity.com/2020/02/13/do-you-need-a-thin-neck-electric-guitar/
https://www.adkguitar.com/blogs/news/what-guitar-specs-to-look-for-when-you-have-small-hands
