What to expect when moving to Indonesia

In your opinion, what's the most important thing to know about Indonesia?

Especially for westerners, forget everything you know about life because it doesn't apply here. Also be sure to pack an open mind - you'll need it.
You should also be fully aware the grim reaper lives on Indonesian roads and is very busy.

When would you recommend someone should begin planning their move to Indonesia?

People plan? I didn't.

Whilst the above is true, as long as you have checked out what you're going to do for money and are sure you can get a legal visa, not much else to worry about so not a lot of planning is needed save perhaps medical insurance.

What were the most helpful ways you found to get organised? For example, did you use a checklist, were there any particularly useful websites or apps?

Make sure your bank cards have a long time left before they expire and make a checklist of stuff you'll need. That includes lightweight clothes but only one light jacket in case you go to a cold area.
As for websites, there's one called expat.com that's essential.
Make sure you have google maps or the taxi drivers could well take you the tourist route.

Don't buy expat medical insurance as it's aimed at expats. The locals buy local insurance and they aren't dropping like flies but they pay a lot less for what is often the same cover.

What advice would you give to future expats preparing to move to Indonesia?

Leave everything like TVs, sofas and all the other heavy stuff at home - you either won't need it or it's a pain to drag with you and likely cheaper to buy new here than pay the cargo costs anyway.

Don't import a car or motorbike unless you enjoy stress and headaches.

Crime is hardly an issue here unless you get mixed up with the low life element. Stay away from the seedy bars, karaoke dumps and anything that looks like prostitution or gambling.

Avoid driving if possible as any accident is your fault, even if the 12 year old unlicensed, uninsured rider of the motorbike with no brakes that hit you was drunk as a skunk.