And based on that, I would say a much more important point is: Earn during promotions, burn when there are no promotions.

Again, this is not a hard rule (because may the properties you need to stay at are super-expensive during promotions and super-cheap when there are no promotions), but all things being equal, when the hotel program is or isn't giving big bonsues, you should factor that into your math. It's one thing to say you'll use points because the rate is over this, but what if that same rfate is earning double, triple, quadruple (or whatever) points on that stay? That certainly changes the math, but if you aren't doing your own math from scratch it's hard to factor it in (except for the simple rule of "earn during good promotions, burn when there's no good promotion for you").