my rule is similar to BigLar, but even simpler
All our travelling are leisure travel therefore I have a very good sense on how much points and miles I would valuate them as every dime comes out from our own pocket.
I just have a simple rule on HHonor points - 0.005 per point - give or take a few percentage point that is not even worth to finetune. :-)
Recent example, we had a redeye flight HNL/ORD/ATL 2 weeks ago. We needed to drive back to FLL. There is no way we would drive long distance after such a long redeye. So I booked a Hampton Inn at Northlake, Atlanta at 7500 pt. For $37.50 cost, it is a bargain to me. On the other hand, I looked at Hilton properties in London/Paris, and looked at what people reported paying for them on Hotwire - there is no way I would burn my points for those properties when they are going at around $100 to $120 on Hotwire. The bottomline is, we dont have to stay in a Hilton. Since all expenses coming out from our own pocket, we have a very different way to value points versus people on expense accounts.