Why do Kevlar strings require extra caution?

Try these steps in order

1. Gather the products, gauges, break locations, and cumulative hours for the last three sets. If a break occurs near the frame rather than through center notching, do not make Kevlar the candidate; inspect parts and stringing condition first. State the problem numerically, such as “Center breakage is frequent enough that the monthly stringing cost is unaffordable.” Wanting a firmer feel or an advanced-player image is not a reason to accept very high stiffness.
2. First test a less-extreme alternative under the same conditions, such as the existing material one gauge thicker or a durability-oriented polyester. If it meets the target life, there is no reason to proceed to Kevlar. If a candidate remains necessary, ask an experienced stringer about the racquet's permitted range, mains and crosses, a softer cross, and a conservative starting point. Do not copy an internet number and order a full bed.
3. Limit the first playtest to a short mini-rally, 10 baseline balls, and 5 serves. Immediately record impact feel, whether you had to hit harder for depth, and whether racquet-face control changed. Stop the comparison if it is uncomfortable. Decide only after tracking at least three times not just break life but normal-swing trajectory, condition after the session and the next day, and stringing cost. Return to the previous material if losses outside the target are substantial.