I was prescribed HRT after 3 or 4 months of extreme instability. I had been diagnosed aged 10. At the time I hit problems, I was 50. I have answered questions like yours on this forum on several occasions previously. If you run a search for HRT you should find them. I was told that only a small percentage of type 1s experience the sort of extreme swings I did, ie. typically 4 point omething mml to 22 mml within 2 hours after my normal insulin and food. As this is potentially damaging over a period of months /years, HRT was considered preferable to letting the situation continue.