Someone taking a snapshot of my Frequent Flyer account totals might think I'm a hoarder -- over 1 million each in United and Flying Blue, over 600K in AA, 400K in Lufthansa, plus ~100K each in quasi-orphan Delta and BA accounts -- but I don't consider myself to be a hoarder.
The "Silas Marner" type hoarder is very reluctant to spend. I'm not. I do redeem regularly for myself and for my SO, and for friends and relatives, and not in a miserly fashion either -- toward the pointy end of the plane. Within the last year I've treated myself to a First Class Europe - Japan RT,
V. and I will fly WBC to Cape Town this fall, and I've redeemed 3 US-Europe and one US-Pacific RTs for friends and relatives, some in business and some not. On top of that, I've burned quite a few United miles upgrading myself on Trans-Atlantic flights.
The thing is that I do fly a lot on business, and I earn lots of miles in a year (although this year I'll probably have a net decrease in my total holdings, which is all right because last year I had a net increase). Also, it's a problem sometimes finding award travel when we're free (CPT was actually our third choice, after BKK/KUL and EZE, for instance; finding two First or Business seats on the same flights over a complete itinerary is not always that easy).
Yes, I do maximize my mileage earnings, but I don't churn credit cards or pay (much) extra to do so. And yes, I'm frugal in redeeming (seldom pay double miles for an award), but I don't insist on the cheapest award flights just to save miles.
Like some, I do see the balances as a sort of "retirement travel account," and I even cringe with each "enhancement" that devalues the miles I have. But I live with it.
I sure do wish, though, that there was some way to earn "interest" on my mileage balances . . .