I use the miles usually on saver business class, that way I feel like it's money (miles) well spent. when a ticket cost $8,000 and I can get it for as low as 100K I feel good about it and think it's a great deal. I also "use" them as much as I can, stopover/add a destination at the end of the trip to get more out of what I spent.

As far as sharing them, I'm flying solo and we don't have a money issue so the fam pay for themselves.
If that was something I should take in consideration I would based it on the case... If I think the trip is count for it, what is the other person options, how many miles I have vs. how much is the trip...