With the world's economic climate the way it is and has been for the past few years many people are cutting back on boiler servicing and general safety checks. You can only get away with ignoring the maintenance of your property before it escalates into a larger job costing more money for so long.
If you happen to rent out the property it is illegal to ignore the maintenance of appliances, especially plumbing. When you rent a property to a tenant you must make sure that the property is safe, these checks need to be carried out annually.
For homeowners themselves, there are no current legal stipulations that state your property must be serviced regularly by a gas-safe plumber, but the homeowner may be liable in terms of house insurance if an incident was ever to occur from a poorly maintained appliance.
The outcome of a boiler not being maintained is a build-up of by-product (burnt gas) which will seriously reduce its efficiency. With gas prices the way they are this isn't an ideal situation to be in.
Efficiency is not the only problem that can come about from ignoring boiler maintenance. When you get your boiler serviced the plumber will look for signs of damage, problems that could hinder your boiler in the near future, they can stop small problems from turning into big problems by getting to fix them sooner rather than later, thus saving the home-owner money.
Having a new boiler installed isn't cheap so it is imperative you get as much out of your existing boiler as possible.