Alternatively, how much of the stats were the same machines failing repeatedly until they found stable settings? [Anecdote] If my brief experience is anything

Alternatively, how much of the stats were the same machines failing repeatedly until they found stable settings? [Anecdote] If my brief experience is anything to go by, overclocking involves lots of crashes until you get it right. Once it is working I would expect no more failures than a shop-bought PC, but by that point the statistics are already skewed by all those crashes that I don't care about.