Change it every 3500 miles if it is a pre 1995 vehicle. If it is a post 1995 Impala change it every 5,000 miles. It will say in your owner's manual. If you don't have one, you can go to a parts store and find a maintenance schedule on the first few pages of the Haynes manual for that vehicle.
every 10,000 miles
Probably every 5000 miles. Or 6 months.
it is recommended that the fuel filter be changed every 15000 miles or 12 months, but if you always drive on empty, you might want to change it more often.
Every 2000 miles
If they are platinum plugs, should be every 95,000 to 100,000 miles.
It is best to change the oil after every 6000 miles. The most important thing is to follow the recommendations for your car.
How often should you change the fuel filter?
Should change the filter at least 2 times a year. Remeber the fuel is always being pasted thru the filter. But if you get to it once a year that is better then not doing it.
Unless there is something wrong with it (there shouldn't be), you should never have to replace the timing chain. That's the beauty of chevy.
Follow the recommendations in your owners manual or change it every 5,000 miles.
I have been told every 40,000 miles to protect the fuel pump located in the fuel cell.
as often as needed