It's best to include the make and model of your boiler.
The age should not be an issue as spares are more than likely to be available. Find a reliable Gas/Bolier engineer (ask friends and neighbours) - in UK must be Corgi registered to legally work on gas boiler. Avoid British Gas at all costs.
Spare parts can be a bit expensive but far less than a new boiler. For a simple fault you may be looking at a £50 charge if you're very lucky and up to £250 if a major item needs changing.
As a guide to the cost of parts you can check here...
http://www.boilersparesdirect.co.uk/parts-online/
Also use the search feature on this site with your boiler type in the box and see the problems that others have had.
Peccavi
December 2008