According to their Terms, points can expire 18 months after being earned if not spent. I'm not sure how diligent they are about this, but you might not want to hold on to all of them for too much longer.

As for HHonors, it seems to be one of the pricier per point means of redeeming points. For 10,000 Mypoints (=10,000 HHonor points, you can only redeem in lots of 10k, 20k, or 50k for miles) you can get 1500 miles on most airlines, or 2000 on American. Assuming you could get $75 in GC for 10,000 miles (which you can, or better if you get Barnes and Nobles or Macy's gcs ) That's about $0.05 per mile, not so great. You'd do better getting gift certificates or even web certificates (which you can use just like a credit card online).

Of course, it all depends on what you're likely to spend those HHonors points on. But shop around a bit - there are some better point bargains on mypoints if you just compare some of the prizes.