Annual, Preventive, Regular Maintenance
No matter what you call it, boilers, furnaces, AC units, and water heaters need to be tune-up periodically to ensure that they deliver their max performance. Now this has to be just a scam from the heating companies to get more money, my heating system has been running fine for years, why should I have some clean it? The jury may be out for how regularly you should schedule maintenance but the general guideline is once a year.
Why you ask, well because your heating system collects dirt, dust and other particles that build up and lower your system efficiency. Making older system even less efficient and making new energy efficient systems seem much less modern. You might still wonder, does it really make a difference, well we are lucky enough to have a testimonial that shows the benefits of annual maintenance. This past winter was on average 15% colder than the previous year's winter, if you ran the same year to year you would use 15% or more fuel without maintenance. However this customer was wondering why they needed annual maintenance when their fuel usage was about the same after having an annual maintenance the year before. In this customers case their heating system was able to 15% more efficiently after having annual maintenance performed on the system.
Now this of course will not happen with every customer, but annual maintenance will keep your system running for efficiently, keep small issues from becoming big ones, and use less fuel.