Every time you change the coolant.
when the thermostat will not open when placed in a cup of boiling water
Change it every time you change your oil, 3 months or 3000 miles. Every 40,000km. More often under dusty conditions.
On the V6 change it when you change the cam belt. On the 4 cylinder which has a cam chain change it when you have a leak or it fails.
I don't know about 2006, in the 2001 it's at 105k miles
Honda recommends changing it at 100,000 miles. I personally recommend you change it every 75,000 miles. The 2003 Honda Accord had problems with the transmission so I would recommend this as a preventative measure.
15000 miles
I recommend every 75,000 miles.
How often should you change the fuel filter?
Change it every 5 years or 60,000 miles whichever come first.
Honda recommends @ 45k miles and then every 30k miles after that.
Every 110,000 miles on the V6 and never on the 4 cylinder.
This is listed in your owners manual. The change interval depends on if you have the CVT transmission, the 5 speed Automatic, or a Manual. Just open and read your owners manual.