As everything teaching "device" (and there is a lot of academic literature studying this, across disciplines, this is not specific to bowed string instruments), fingerboard tapes or any kind of marks on or on the side of the fingerboard should not : be used systematically without observation phase
be permanent be used alone without having an exit strategy (see point 2.) be used as a way not to address underlying difficulties and fears of the pupil be used as some parents use a pacifier (see also point 4.)
given just to spend your time on what you like to teach instead of what needs to be done for the pupil (related to point 5.).
All these points are related, I will try to elaborate further later.
Other less common devices posing the same problems include special bow guiding devices, simplified or heavily modified music notations.
music.stackexchange.com/users/48/ogerard
I use fingerboard tapes for beginning students, but only 4 of them.
I would not recommend using those pre-fab stickers that have placement lines for all the whole steps and half steps in first position.
This is overkill in my opinion and can create over-dependency, or actually be more confusing than necessary.
If you're teaching beginning children most likely they will need some finger guide to help train their ear.
As soon as they can hear where the fingers go then take the tapes off (when they move up to a new size instrument is a good time to assess their new tape needs!)
If you're teaching beginning adults it will depend on the experience of the adult.
If they have a good ear they may not need any tapes at all.
If they have trouble finding where to place the hand, but then are fine after that perhaps use just a first finger tape.
Using all 4 of the finger placement tapes in first position is also fine if they need it.
Again, just keep on top of when they don't need the tapes anymore
so they don't become to reliant on them as a crutch.
We're always looking to use the tapes as a tool to train the ear, not as an excuse to not have them listen closely and adjust their fingers by what they hear.
music.stackexchange.com/users/32879/Emily Williams
It is helpful to some, but sometimes can create dependency.
I have been playing the violin for a year and a half, and I sometimes take off a few tapes, just a few weeks after mastering a piece, just to see how it goes, and I can do pretty well without them.
I have been using them less and using my ears for intonation.
Though, they are important at the beginning, as it is hard to understand where the fingers go.
Tapes can be used as a good reference point for some positions, but it is different and may vary in people.
I know people who can play without tapes at the beginning, and some who struggle without them.
music.stackexchange.com/users/65543/Newbieviolinist
My teacher used a pencil to lightly draw a line on the board.
That way I got the benefit of seeing where I should place my fingers, and learning to hear where I should put them without learning to be dependant on them.
music.stackexchange.com/users/119/iarwain01
I personally never used fingerboard markers when I learned violin as a child.
However I see that here in US, most beginners use them.
I think they are helpful especially for the young child until they learn how to listen and hear the pitch, especially if they have not played piano before playing violin.
I would however remove them when the student gets better at identifying the correct pitch.
music.stackexchange.com/users/735/rodica
As a tech, it makes it very hard to have a properly set up violin, especially as most cheaper violins come with higher tension and lower fingerboard clearance steel strings.
To set these up to work, I would be replacing or shimming the nut, replacing the bridge, and setting up the instrument above height to accommodate for these ridges that are now added.
Even the appliqués require an increase in spec height by the thickness of the appliqué on both the nut and bridge.
Then again, most of the time, it's someone who has applied 2 layers of tape, effectively making frets...
music.stackexchange.com/users/6031/MIchaelD
I’m 41 and have been learning for just over a year.
I’ve taken off my tapes but found that over time my finger placement starts to become less accurate.
I can hear the difference but struggle to pinpoint where I need to place my fingers.
I put a black tape at 1st and 3rd positions and that seems to do the trick for me.
I’d rather spend the time learning a new piece than trying to get the intonation without tapes.
I don’t plan on playing professionally
but I’d like to eventually play without them, but for now, the tapes are staying.
music.stackexchange.com/users/66877/Heath Cobb
Some teachers use them and some don't. I've heard that they can become a crutch and cause delayed ear training development, but others say they are necessary at the beginning.  Can they really cause problems? Has this been studied in any kind of way? Has it been addressed by a respected author? Should they just be used because they make life easier?  Thanks,
Should fingerboard tapes be used for beginner violinists ?
music.stackexchange.com
<violin><teaching>
music.stackexchange.com/questions/111
music.stackexchange.com/users/109/Lilitu88
Fingerboard tapes are needed for children learning violin. For beginner adults, it depends on their experience. If they have a good ear, they may not need tapes. They are important at the beginning, as it is hard to understand where the fingers go. As soon as they can hear where the fingers go then take the tapes off (when they move up to a new size instrument is a good time to assess their new tape needs!)   Finger tapes can be useful for beginner violin players, especially children For adults it will depend on their experience and their musical ear. They can cause dependency, so should be removed when they can itentify the pitch.
Finger tapes can be useful for beginner violin players, especially children For adults it will depend on their experience and their musical ear.  Finger tapes can cause dependency, so should be removed when they can itentify the pitch.