The soldering iron is probably one of the most important pieces of equipment that you will need when making stained glass art. The soldering iron needs to keep temperature throughout the solder run to keep the solder liquid a flowing. I have been using the Hakko FX-601 as it does keep temperature and does perform very well.
The Hakko FX-601 does have an dial to adjust the temperature. It also has interchangeable tips. I have replaced the tip once on the soldering iron once in my 5 years of usage. I do have other tips which are 1/4in in width. This is the maximum size that can be used and is ideal for soldering stained glass. I am currently using the 7/32in tip and it works very well. People tend to go for the wider tip though. When I have to change tips next, I will go for the 1/4in tip.
It is important to keep the soldering iron tip clean. This will extend the life of the tip as well as the soldering iron. Having a damp sponge to wipe the tip to get the dirty solder off seems like the preferred method. And try to only keep the soldering iron on for as long as needed will also extend the life the tip and iron itself.
Now keep in mind, if you are looking for the Hakko FX-601, don’t go right to Amazon for the cheapest price. A lot of the cheaper “Hakko FX-601” soldering irons have been counterfeit ones that do not hold temperature or fail within a month of using them. So do your research and I would recommend purchasing one from a stand glass retailer.