Assuming we’re not talking about fixed-value points currencies like those of Virgin America or Southwest, the marginal value or incremental value of a point can vary wildly. This is due to the fact that most loyalty programs have redemption levels, and if your points haven’t reached a given redemption level, they’re not really worth that much.
Let’s say that you want to take advantage of a gem in the US Airways redemption chart: 90,000 miles for a roundtrip business class ticket to North Asia (which generously includes Hong Kong and Taiwan). If you have 89,000 miles in your account already, an extra 1,000 is quite valuable to you, since that would give you enough miles for your redemption; if you had no miles in your account, then 1,000 is still better than nothing, but you’re still a long ways away from your business class ticket. In the former case, it might make sense for you to buy those miles outright, even if US isn’t offering a buy miles promotion, while I don’t think it would make sense to buy only 1,000 miles in the latter case.
I think there are three lessons to learn from this: 1) try to concentrate miles in a few programs, rather than collecting miles across many programs; 2) programs that offer one-way awards are better for the general population; and 3) SPG can be extremely valuable.
Lesson #1: This is almost self-evident. It’s better to have 90,000 miles in US Airways than 10,000 miles in each of ANA, Aegean, Air China, Air Canada, Asiana, Austrian, Avianca, Miles and More, and EVA Air. I know I can redeem those 90k US Airways miles for a great award, while 10k won’t get you much of anything in most programs. This is why it’s useful to choose a select few programs to accumulate miles in, such as United for Star Alliance flights and Alaska Airlines for flights on Alaska, American, and Delta.
Lesson #2: The biggest reason why I think that programs that allow one-way redemptions (e.g. United, American) are better than those that don’t (e.g. US Airways, Delta) is that the former programs have lower redemption rates than the latter. While the minimum redemption in a program like US Airways is 10,000 miles for a roundtrip within Hawaii, the minimum redemption for United is only 5,000 (for a one-way intra-Hawaii flight). If you don’t fly much, it’s much easier to get enough miles for a one-way redemption in a program like United’s as compared to getting twice as many miles needed for a roundtrip redemption in a program like that of US Airways.
Lesson #3: SPG points can be transferred to almost every airline mileage program at a decent rate (United being a big exception), which means that SPG points are extraordinarily useful for topping off accounts that are close to particular redemptions. This makes SPG points a little like the ultimate points currency because they’re so flexible, as opposed to miles in general which usually can’t be transferred into other forms (or even other accounts) easily. This is one of the main reasons why so many bloggers recommend the SPG Amex to beginners.