Low mileage (about 5000 miled annually), how often should the plugs, filters and oil be renewed. I do it every 6 months.?

Spark plugs in a modern engine with electronic ignition can last for 100,000 miles! Changing them every six months is a serious waste of time and money. I'm comfortable with changing my oil every six months, although the vehicle manufacturer says I can go up to 10,000 miles between oil changes.

READ the owner's manual that came with your car. There is a whole section on servicing the vehicle, and a schedule for doing it. If you stick to the manufacturer's recommendations, your car should last a long time.

Your wasting money, plugs dont need to be changed that often.

Regular motor oil needs to be changed every 3,000 miles or 3 months. Which ever comes first.
Spark plugs that are regular copper plugs go 30,000 miles.
Platinum spark plugs are good for 60,000 miles.
Iridium spark plugs are good for 100,000 miles.
If you have an automatic transmission change the ATF every 60,000 miles. DO NOT FLUSH the tranny.

you love throwing money away ..plugs will last 50.000 miles ..at least ...oil every 12000 miles ..or yearly ...and yes i know you americans love to change every 3-5000 miles ..but tell me this .they sell american cars in the uk ...chevrolet sell its people carried /suv ..its service interval ? every 12 months ..or 20000 miles ..mustangs is every 12000 miles ...any one with an answer?

At 5,000 miles per annum then annually will be more than enough for oil and filters, bi-annually for plugs

Depends on the vehicle, its age, its condition and the type of driving. For a "typical" car driven only on roads with that mileage I guess you need change only every 2 years, but I'd do it once a year when having it serviced and its MOT check.