Strings (tennis)
The material used in tennis string can significantly affect a player's performance, and even health. Several materials are used to make tennis strings. They vary in terms of elasticity, durability, rebound efficiency, tension holding capability, and manufacturing cost, among other considerations.
Guitar tunings
Some alternative tunings are difficult or even impossible to achieve with conventional sets of guitar strings, which have gauges optimized for standard tuning. With conventional sets, some higher tunings increase string-tension until playing requires more finger-strength and stamina or even until a string snaps or the guitar is warped; with lower tunings, strings may be loose and buzz. Therefore, many alternative tunings benefit from re-stringing of the guitar with string gauges chosen to optimize particular tunings by using lighter strings for higher notes (to lower tension) and heavier strings for lower notes (to prevent string buzz); tone is also negatively affected by incorrect string gauge choice.