After many yrs, it will clog also. But clog the valve O ring and stuck the nozzle. GI is using because it cheaper.

Doing a lot using GI pipe as gas piping. Even for bigger gas pipe which using flange to joint.

The best is still the copper pipe. And for easy work, just use the flexible copper pipe. Cause the diameter is just fit nice to the hose. And tighten with the hose clip.

How long it last very much depend on the vapour content in the pipe. Who will open out the GI pipe and check. Most of the people don't no and thaught the burner have problem when the

1) turn the knob higher to get more frame
2) yellow frame
3) totally no frame.

But this is very easy DIY. Just unscrew the nozzle, knock the nozzle till the dirt out. If too stubborn use a needle or what ever match the nozzle size hole, poke into it. But don't poke too hard till the hole big. Some of this nozzle is make of copper.

For o ring, change  it, oil it and clean the internal.