Practice mutes can come in very handy! I use them a lot myself! They are great when you are traveling and have to stay in hotels, or if you live in an apartment or have family you might bother with late practice sessions etc. I use my mute when I am “working” on new music while my family is around. But once I am ready to start preparing a piece for performance, or fine tune my technique, off with the mute!
As mentioned by others, the mute does hide some imperfections and you will not be able to practice proper bow weight for the dynamic changes within the piece. The mute tends to hide some of the details that are so important in music. So I would not recommend always practicing with the mute. In fact, I would not do more than half of my playing with a mute. But if muted practice is your only option, make the most of it! You will still be able to move forward.
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