I have to disagree with everyone who said SWUs so quickly. If you only have 6 (or 8 or 10 depending on how much you fly), you have to value them much more than a couple of hundred thousand miles. For me I fly LHR-JFK roundtrip once a week, usually in H class, and have never used an SWU to upgrade. I save them for when I fly to SYD in W class. So the real question is, if you're going somewhere later in the year that would a) require more miles, or b) be on a lower fare class, then you use the SWU. If not, you should most definitely save them, as they are much more valuable. The other thing I should point out is that if you are waitlisting for any of you flights, apparently SWUs have a higher priority for clearance than MP upgrades. But I've never actually seen that to be the case. However, if, as you've said, you're not sure that you will be travelling anywhere else internationally this year, use them. You'll still have at least 4 left, and worst case scenario, you can use them to upgrade to a nice 747/777/p.s. domestically.