A typical condensing combination boiler will last you approximately 8 - 12 years but here a few ways of increasing the lifespan of your boiler.
Its always a good idea to have a magnetic filter installed as it stops the sludge from your radiators reaching your boiler and blocking parts within the boiler. Magnetic filters should be cleaned annually and inhibitor should be added.
Power flushing will help get rid of sludge within your system which will improve efficiency by sending water at a high velocity though the system to dislodge and remove debris, limescale and sludge. Sludge can cause a lot of damage to your boiler and heating system so the less you have the better.
An annual service will help you potentially spot a problem with your boiler before it breakdowns and you are left without heating or hot water. It will also ensure your boiler is safe to use.