Servicing - do I need to change spark plugs?

I have been offered an full annual service at a Citroen dealer for £300 for my four-year old C1, or a deal at £200 by the same garage for a service that mainly differs in not changing the spark plugs. How necessary is it to change them each year? The car does about 3000 miles a year as a runabout around south west London.
They don't need changing each year. No more than every two years.
Answered by Honest John on

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