When should I change the oil and filter?

I own a Vauxhall Zafira, but find that fully synthetic oil costs an arm and a leg. I only cover 7000 miles a year and am told that some engines are happy for this type of oil for two years or 20,000 miles. Would it be wise to change oil every say two years or should I opt for semi synthetic and change yearly?.
All engines need a change of oil and filter and air filter at least once a year or 10,000 miles, whichever comes first.
Answered by Honest John on

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