How many solder joints can your tips do?
It varies by the tip geometry, the thickness of the tip’s iron coating, the temperature settings, the solder, the flux used and the operator skills.
JBC features tips which can perform up to 100,000 solder joints.
How often and when do I need to use the tip tinner?
The tip tinner / cleaner is a chemical method to clean and retin the tip at the same time.
It should be used only when alternative methods fail (i.e. sponge, brass) and a very active cleaning method is needed.
Do I have to change cartridges anytime I want to solder at a different temperature?
No, you are free to choose any temperature with any cartridge. If desired the temperature can easily be locked at a fixed level.