In years where my travel has been scant, I've just waited until later in the year to see what I need to make it... and decided whether it was worth it with that knowledge in hand.

Is it worth it to spend $1000+ to get to Silver? I don't think so. If you have the first bag fee waived already, I don't see strong financial motivators to spend that much for Silver. Tiny elite bonus, "premium" seats, early boarding, elite desk, and occasional upgrades aren't worth that to me if I don't really have the money. But if you find yourself a few thousand miles short, that's a different story! Then a carefully chosen run could finish things up for very little, and maybe you'll get a fun trip out of it.

I frequently finish my year with a trip to Florida or California just to get a few more miles. A few days on the beach isn't such a hardship...