One of the most important jobs when setting up your guitar is to ensure that you get the neck as straight as possible. Necks that have a bit of a bow to them can be difficult to play, and they will often have intonation issues.

How To Tell If Your Guitar Neck Needs Adjustment?
In most cases, you will be able to tell that your guitar neck needs adjustment with a quick look. In other cases, you can hear when the neck may need a bit of adjustment. For example, there may be fret buzz, and maybe some intonation issues.
In most cases, we recommend that you go to a professional to have your guitar set up properly. However, once it has been set up properly, you should be able to carry out most adjustments yourself. All you really need is access to a feeler gauge, and a truss rod key (pretty much just a hex key, but longer)
As we said, a lot of the time it is going to involve nothing more than looking at the guitar neck.
We suggest that you hold the guitar up at eye level. You can then look straight down the neck. You will be able to see whether the neck is straight or not like this. If it is off at a slight angle, then it may need a little bit of adjustment.
If you notice that any strings are touching the frets, then there is a good chance that your neck isn’t straight either. Your neck may also not be straight if the strings are sitting too far from the neck of the guitar, which can make it difficult to play.
You can hear when the strings are touching the neck because there will be a small amount of fret buzz, You may also notice that the tone is slightly off on some parts of the guitar.
How Do I Know If My Guitar Neck Is Straight?
As we said before, you will be able to tell that your guitar neck needs adjustment with a quick visual look. However, if you are serious about getting that guitar neck as straight as possible, then we recommend that you use a feeler gauge.
The job of a feeler gauge is to measure the distance between the fret and the string. You want that string to be at the perfect height. You don’t want it so low that it touches the fret with barely a touch, but you don’t want it so high that it can slow down your playing.
We can’t provide you with much guidance on the exact distance between the string and the fret here. This is because it will vary based upon your playing style and the guitar that you are using. For example, fast players generally need the strings to be closer to the fret. We are sure that you will be able to find guides on string height for your guitar and preferred playing style.
Using a feeler gauge isn’t too difficult. It is a tool used to measure small distances. Essentially, it will be small metal blades that you slide between the string and the fret. The size of the blade that you need to use will tell you the height.
You don’ät need to measure every fret. Most will measure around the 7th fret. If the distance between the fret and the string is more than 1/2mm, then you will need to adjust the guitar neck.
Should a Neck Be Perfectly Straight?
Maybe.
It really does depend on the guitar.
The general advice is to get the guitar neck as straight as you possibly can get it. For most players, you never want the guitar neck completely straight, though.
How straight your neck should be will be dependent on your playing style. Some people are able to cope with straighter necks than others (most people want there to be a little bit of a bed in the neck of the guitar)
In other cases, the guitar will be the problem. With many guitars, if you straighten the guitar neck too much, then it will suffer from intonation issues.
The best advice is to get the guitar’s neck as straight as you can. Add a bit of a convex bow to the neck, but not too much. This will take a few hours as you will need to make small adjustments to the truss rod, and then the guitar should be left for a few hours. Most people recommend no more than 1/4″ adjustment at a time.
Once you have managed to get the neck almost straight, you can mo
Once you have managed to get the neck almost straight, you can move on to adjusting it for your playing style. So, play the guitar a little bit. If it doesn’t feel or sound right, then you may want to add a bit of a curve to the neck. If it plays perfectly well, then try and kick it up a notch. Again, you should only be adjusting 1/4″ at a time and then leaving for a few hours.
How Do I Know If My Neck Is Warped?
A neck warp on a guitar can be difficult to spot. This is because it is often going to be difficult to tell whether the guitar neck is warped or whether it just needs a bit of adjustment. If the neck is warped, then you need to replace the guitar neck (or the whole guitar)
If the guitar neck is warped, when you look down the guitar neck, you will be able to see the warping. If one side of the neck is lower than the other and you can’t straighten things out again, then there is likely to be a bit of warping in the guitar neck. A guitar neck should always be straight across the same fret, even if the neck is not completely straight itself.
You will also be able to notice intonation issues if the guitar neck is warped e.g. fret buzz, etc. This is why it is so difficult to tell whether a neck is warped or just not straight. It will be the same symptoms.
Conclusion
It is easy to tell if your guitar neck needs adjustment. If the strings are too close or too far from the fret, then you will likely need to adjust the truss rod a little bit. You can either do this yourself or call in a professional.