Passport Conundrum

I need advice! My passport is set to expire in March 2012... when I'm in Chile. The question is do I renew it now or do I renew it when I'm there? And there lies my conundrum.


Reasons to renew in Chile:
- It costs $110 for a new passport and then it will cost another $130 to get my visa when I enter Chile (the tourist visa is good for the life of the passport)
- If you change your name within one year of getting a new passport you can have your name changed in it for free. If it has been more than one year you would have to pay another $110 for the passport (and pay for another visa as well)
- I am planning on getting married and changing my name... but it will probably be a few months  over that one year mark
-So if I can put off renewing my visa for a few months I wouldn't have to pay for my passport twice. I may still have to pay for my visa twice. But this is the main reason: I save at least $110 and I also put off having to spend $240 for awhile.
- I emailed the U.S. embassy in Santiago and they said that if I was living there and my passport expires I can renew it with them.


Reasons to renew before I leave the US:
- What if since I would not be living in Chile permanently at that point the embassy decides I broke the rules for renewing it? What are the rules for renewing your passport abroad?
- What if something goes wrong and I get deported?
- The reasons here are mostly my worries. Some are blown out of proportion I think, but they still worry me.
- Convenience. If I renew it here I can just mail in the application and a check. If I renew it in Chile I can possibly mail it in but I might have to go to Santiago (a two-hour trip) to renew it.


What do you think? Have you (or someone you know) ever renewed your passport when you were abroad? Any advice would be appreciated.