I would say by my actions I am a hoarder but definitely don't intend to hoard miles. I tend to want to save them for expensive trips in premium cabins, but inevitably the tight capacity controls on awards, combined with my not-that-flexible schedule force me to hoard rather than spend.

It is definitely bad because the miles get devalued over time.

The other factor at work is the desire to fly on paid tickets to maintain elite status. It is very easy to tell yourself 'I'll fly now for the miles, then use the awards next year.' Somehow, next year never arrives.

Regards,
Traveler