If you do not play the violin or seen one up close, you may misconstrue that parts of the violin are not removable such as the bridge which can actually be moved rather easily and is just balanced in its place by the tension of the strings. Upon loosening the strings, the bridge will come off as it is not glued on.
Almost the entire violin can be taken apart just like it has been put together, which is why a very delicate part such as the neck needs to be well taken care of as without care, the violin’s neck can collapse and this would affect the string height and the violin being acoustically balanced or even in some more extreme cases, the violin would not be playable. Humidity plays a large role in the expansion and contraction process of the fingerboard/neck area. (For more on this, do read this article from Strings Magazine) As the neck is in constant pressure with the tightness of the strings pulled all the way from the end pin of the violin to the pegs at the other end, it is only a matter of time that the entire Neck angle is affected and not where it is supposed to be. And when the violin is played even more pressure is exerted with the fingers and the bow. That’s why it is important to keep the violin in an ideal environment. (A tip on care for this is to leave desiccant gels in the violin case if you live in a hot humid tropical country like me or during the more humid summer months.)
During the Baroque period (1600-1750), where the fingerboard was shorter, the neck angle was also in a kinder position that the strings could be closer to the fingerboard. However, when the concert halls became larger than just chambers or rooms where the violin was being performed, more projection was needed and sought after. The fingerboard was extended to take in a higher range of notes for the compositions in the Romantic Period of Music (late 18th and early 19th century) radically changed the angle and position of the neck of the violin. Inserting and setting the neck had to ensure a more stable method. Do read Michael Darnton’s article on how to set a violin’s neck, he goes into great detail on the specific measurements and method.
If you suspect that your violin neck was not set correctly as it is visible that it veers towards an angle or to one side; if you feel difficulty pressing the strings than previously felt when u first got your violin, this could be due to changes in the string height. If it is ruled out not due to your bridge, do not despair as this can be repaired by a good violin luthier such as Andrew Carruthers who has extensive knowledge and experience with neck repairs. This repair could really alter the sound of a violin and it could be a night and day effect! So do go and check on your necks, you never know how your violin (or you) may be suffering.