Why to cut the rackets Strings Reasons Reason 1 If Strings are broken then the remaining strings put asymmetrical pressure on the rackets. If that tension is very high then racket frame will break. for example if the mains break after the knot That is zone 2 then there are 70%-80% chance that racket frame will break. If the Strings break in the Middle of the racket that is zone 1 then the weight is will be adjusted a little bit so the chances of breakage are reduced to 20% - 40%. We usually cut the strings to equalize the tension on the frame so the racket won't break. There is a amazing video of how to cut the strings from Badminton Central on Youtube I would additionally want to add is you should start cutting the strings from the opposite side of the broken string. & try to cut it in 1 go. Reason 2 The String looses the tension after stringing since they are multi filament. If the tension becomes unplayable then you should cut the strings. Reason 3 You don't like the string you currently have. Reason 4 There is new string in the market. Which you have to Try. Reason 5 If strings do not mach your playing style. What are your reasons to change / cut the strings.