I have three or four old (like 40 years or more) large wattage soldering irons and never have had the heating element burn up. The usual failure is the conductors in the power cord break and separate beneath the insulation near the handle from too much bending. The other somewhat common failure is the connection from the power cord to the element nichrome wire which often can be repaired with a tiny screw, nut, washer combination. The tips are solid copper and often can be filed to the desired profile and simply tinned with solder (the old school way).