Even if you take all the precautions in the world, sometimes your tights get laddered. It’s best to fix the situation by dabbing some nail polish on the ladder. You can prevent the problem from getting worse, as the ladder will not expand.
This is true, especially when it comes to your thighs! Denier refers to the number of threads in a single yarn of the fabric. A higher denier indicates a thicker fabric. Try to go for tights with a higher denier to avoid having them rip. Instead of buying a smaller size, simply choose a larger one.