Typical Lengths of Use of Things 4 Strings® bow accessories: 

Bow hold learning time varies quite a bit from player to player. 

Each accessory may be removed and re-attached as necessary. 

Early use of our bow accessories re-allocates time previously devoted to bow hold exercises and corrections to the work of advancing more quickly through other beginning material. 

While length of use varies, we recommended removing the accessory before spiccato. Personally, I like to remove the "frog" (index finger and thumb stabilizer) first, while leaving on the Hold Fish®, to help stabilize the pinky and keep the hand in place while students learn the independent functions of each finger. Because these accessories have been designed to not preclude the natural points of contact between the fingers and the bow, continued use, even after no longer needed, will not impede further development of the players' bow hand technique.

Factors affecting length of use include student age, experience and teacher preference: 

Players using the accessory from Day One often find their bow hold has gone into muscle memory after just a few months. Otherwise, during the second or third book of a method, or during the second semester for older beginners, or during the second year for younger students are good times to remove the accessory. The very young may require a longer period of use.