There is no standard rule. If you feel you are ready to take them off, talk to your teacher about it. When I was first learning, my teacher put some little dots on my fingerboard, and they wore off very quickly. In middle school, when I joined the string class even though I could already play, my teacher put them on everyone's violin. We were never told it was time to take them off. Most of my classmates just did not bother to replace them when they fell off. I don't have my students use them at all. Looking at the fingerboard sometimes causes the head, the scroll to point downward, and the violin to slide off the shoulder. These things result in bad habits. On top of that, it delays muscle memory and ear training because you are more focused on using your eyes than paying attention to how it sounds and feels. It also delays sight-reading because your eyes are focused on the fingers rather than on the music. People who learn with finger tapes are often uncomfortable playing things they have never heard because their instinct is to look away from the music to check their fingers. If you can't predict what note is coming next, you can't look away.

None of that is intended to criticize your teacher for using them, though. The advantage of tapes is that you can get someone playing right away. You don't have to take time to explain things or help them find the right places with their fingers. I have heard teachers who don't use tapes claim that those who do are lazy. I don't think that's fair. If you are in a classroom full of students instead of one-on-one, you have to take shortcuts. If you have an adult student with no musical experience or a small child whose parents intend for them to be on their own for practice from the beginning, you can sometimes build confidence with finger tapes and therefore hold that student's interest a little longer. Every teacher does things differently. The best thing for a student to do, provided their teacher is competent, is to default to their teacher's advise on issues (like finger tapes) on which there is some disagreement from one violinist to the next.