Surgery - Colorectal. In brief: Yes, most docs can. Most hemorrhoids should first be treated by conservative measures, such as bulking the stools, education to avoid bad habits like straining, sitting for long periods of time, etc.
Either system will have a burner. 23 years may very well be beyond the typical life expectancy of a oil burner, but a furnace or boiler should last considerably longer than 23 years. The boiler of my house here in MA is 58 years old and still works fine. I am starting to consider replacements, however.
Multiply the hours of burner operation by the gallons per hour to find out the gallons per day your furnace will use. For instance, if your oil burner uses 1.7 gallons per operating hour and it runs for 13 hours per day, it will burn 22 gallons per day. Divide the capacity of your fuel tank by the gallons per day to find out how long the tank will last. If you have a 250-gallon tank, and use 22 gallons per day, divide 250 by 22 to estimate an 11-day fuel supply from your tank. Calculator.