sooooooooooooooooooooo, if you only use your Oil furnace for Hot water year round,
seems it's ok to have it serviced every other season I assume.
Depends on your level of comfort! My wife insists on having yearly service, although I have "missed" a year!
Do nozzles really wear out so that it has to be replaced every year? Comparing to a TDI Beetle I once had that got 50 mpg, and let's say burning 1000 gallons of heating fuel, that would equate to 50,000 miles. My injectors were going strong when I sold the car at 225,000 miles. Granted, they're probably made better.
Totally different fuels! Apples and Oranges!
Bill