When my 95 year old aunt receives these, she puts them in the freezer for a while. She says freezing makes the nylon last longer. She wears these support hose every day and I've been buying approximately 3 pairs a year for her. But don't put Berkshire out of business! She needs these.
Compared to L'eggs Sheer Energy, these are far more durable and more comfortable. They hold their shape well and never sag or pull down. The fabric is silky, doesn't cling to clothing, and holds up to repeated washing (gentle cycle in a hosiery bag). I have noticed that a couple of pairs have developed runs in the toes but there is a guard band at the toe that arrests the run so that it never travels up the leg. I have been able to wear these pairs repeatedly without any further damage.