I dont hoard, but I do like to keep the total at circa 300,000 minimum at all times (and I usually always book 'big' holidays 12 months ahead).

My logic is that if the Avios points earning came to an end, or if my work habits stopped me earning in the quantity I do, I'd still at least have another two years after that in which I could F long-haul to the USA with a 2-for-1, or three years if I slummed it in J.

I'd never get to two million though!