We use them for learning sometimes, but ultimately we don't have markings because we don't actually need them. It seems massively intimidating when you start le

We use them for learning sometimes, but ultimately we don't have markings because we don't actually need them. It seems massively intimidating when you start learning (or contemplate learning), but the muscle memory of where to put your fingers, and the ear-finger feedback cycle to keep you in tune can develop very quickly. It does require a good sense of relative pitch, which the student may need to develop first, but this is not unique to the violin. Singers and trombonists are obviously in need of a similar thing, as are theremin players, but slightly more surprisingly to those who don't play them are reed players, who have an incredible ability to play out of tune by simple adjustments of their lips around the reed, and recorder players, who can play horribly flat just by not blowing hard enough into the instrument (or too sharp, by blowing too hard). Stickers on the fingerboard can help us when we don't already have the relative pitch sense, because you've got to learn it somehow and "go learn another instrument first" is not a very encouraging strategy! There are actually products you can buy which are basically a sticker for the whole fingerboard laying out a fret pattern but without the physical attributes of frets, which would alter the sound of the instrument and reduce the ability to play slides, but I don't know anybody who's got one. It's not as big a deal as you might think before you start. I say that as someone who, before taking up the violin, learned to play the viola da gamba in part because it has frets and this was far less scary (learning to use a bow was scary enough). I still play both, and the playing technique on the viol is very definitely informed by the presence of the frets and their effect on the sound.