soldering iron tip help?

Sounds like your iron is getting to hot or your using very cheap and very thin tips, get some nickle plated tips keep them clean and don't press so hard.

Maybe you are using acid flux? Normal solder is a lead/tin 60/40 composition, with a rosen core to provide the flux. You don't normally need any additional flux. I have an old iron like yours, and it is still using the original tip. If you can upgrade to an adjustable temperature controlled iron, the tip should last even longer. Plus you can buy different size tips for different soldering jobs.

I had a similar problem with a inexpensive soldering iron. wondered the same thing myself. One thing I learned form my wife's stained glass making is that you can use a wet sponge and frequently wipe off the extra solder that is on there. My guess is that extra solder contributes to the tip shrinking.

Cheap tips. Get nickle plated tips, keep them clean with a wet sponge, what kind of flux are you using? Use a lower wattage iron.

I think your Iron is no good get a new one I have never had that problem and I repair Boards good luck