You need to find another to make sure you don't forget. This is not the only promo I've run across where you would earn far less (maybe nothing) if you registered "too early". (It may or may not be the first on at SPG, but I've certainly run into plenty of promos at other programs where for one reason or another you could earn more if you waited until you were ready to at least reserve the first stay before you registered.)

And in most if not all such cases, changes were not permitted. These promos are intentionally set up that way, because they know that some people will register "too early" just to get it out of the way. Remember, if you registered "too early", SPG likes that because they don't have to give you as many points. It's not to their benefit to encourage you to register as late as possible (or to alllow you to change your mind later), ti's only to your benefit.

Changing your mind later would require cooperation from them, which you're not likely to get. Regsitering as late as possible requires no cooperation from them (just requires you to figure out how to remember to register without actually registering as early as possible).

In my case, in fact, "as late as possible" (June 30) may still not be late enough. I don't know that I'll know what any of my possible SPG stays in Aug/Sep might be by the end of June (all I'm likely to know by the end of June is whether I expect any SPG stays in July and what those would be, but the answer to that in my case is likely to be "none in July").