Every car owner has to do it at least once every 10,000 miles. However, the cost of servicing a car can vary greatly.

Service prices on selected models may vary across the State by up to £35 for identical, or similar, work conducted on the same car despite dealer's recommendations on prices and how long the work should take.

Car manufacturers set service requirements and intervals for each make and model. In recent years, the length between recommended servicing has extended as improved technology and better quality motor oils came onto the market.

"Each manufacturer has a service book supplied with every car on the road, it specifies the suggested intervals and particulars of service," says Mr Robert Prole, assistant chief executive of the Society of the Irish Motor Industry (SIMI).

Mechanics are expected to refer to these books when conducting routine maintenance, he said.

"Some garages do menu pricing in relation to services. They have on display what can be done. You should specify what needs to be done and ask what the regular service includes," says Mr Prole.

Regular service standards vary from garage to garage, but for a minor service most include replacement of the engine oil and oil filter, check of the brakes, tyres, electrical system, fluid levels and a general check of the car. The service does not always include replacement or check of spark plugs.

Ireland's two best-selling cars, the Toyota Corolla and Ford Fiesta, need servicing at 6,000 miles (9,000 for newer models) or 10,000 miles respectively.

Toyota Ireland's price maintenance schedule recommends a 6,000/9,000-mile service on a petrol Starlet/Corolla for a price of £50. It should include: replacement of engine oil, oil filter, windscreen washer fluid and drain fuel filter. Inspection or adjustment of oil and fuel levels, air filter brake pads and discs, oil and fluid leaks, tyres, condition and pressures, electrical system, road test and report.

Despite this suggestion, prices charged by franchise dealers and independent garages may be significantly higher. Additional services such as spark-plug replacement, higher overheads in cities and variable labour costs may contribute to this discrepancy.

"Overheads in the city are higher than in the country, so prices may be higher in Dublin," says Mr Michael O'Brien of Toyota Ireland Service Development.

However, a random survey of franchise dealers throughout the State showed that the most expensive prices are charged outside Dublin. This may be a result of moves by Toyota to keep Dublin prices low. "We've worked hard for standard pricing in Dublin for routine maintenance," says Mr O'Brien. With an estimated 175,000 Toyotas on Irish roads, service is a good business for dealers and garages.

Labour costs comprise close to half of all routine service work. "Charges for labour can vary considerably from £19 to £30 or more an hour," says Ms Margaret O'Shea of SIMI's complaint service.

Prices quoted by Toyota franchise dealers show that a 6,000-mile service for a 1992 Toyota Corolla ranges from £45 in Galway to £80 in Roscommon.

The labour charges included in this price vary from £24 in Galway and Tipperary to £48 in Roscommon. The suggested task time for a minor service on a petrol Toyota Corolla is 1.7 hours.

Ford Ireland uses a different system to recommend service standards. "Ford does not set a standard price for car servicing, but sets a time allowed for different services," says Ms Carol Ann Heavey, public affairs manager for Ford Ireland.

The range suggested for an annual standard service, or 10,000 mile service, on a 1992 Ford Fiesta is 0.7 to 1.5 hours, she said. Newer models have a shorter range from 0.7 to 1 hour.

The new Ford service schedule for a Fiesta includes the renewal of engine oil and oil filter and a general check of the car. Prices will vary according to the franchise's retail charge-out rate, competition and location, says Ms Heavey.

The survey revealed the service cost for a 1992 Ford Fiesta for a 10,000-mile service may be from £40 at a Ford franchise dealer in Roscommon to £70 in Tipperary.

Labour charges included in these prices range from a low of £23 in Roscommon to a high of £43 in Waterford.

Car service prices and practices are not standardised in Ireland despite attempts by manufacturers. Some franchises choose to include more in a standard service, some less, but often this is not directly related to the price charged.

Even the industry's representative body has its hands tied.

"We're not allowed to get involved in pricing," due to competition authority regulations, says SIMI's Mr Prole.