Like I said, I really don't believe it is all about the quality of the butane, otherwise my results would be consistent when using the same refill cannister to charge many different lighters, and certain ones consistently failing while others seem wholly unaffected. Perhaps it is a combination of bad fuel and a more sensitive setup, but that still means some lighters are just better built than others.

I too had a butane soldering iron that I used for years and no matter what type of butane I put through it it never gave me cause to curse. Then I was issued a different model and it worked good the first tankful then never again.

My culinary torch (the ones they advertise for toasting creme brulee) has been going strong almost a decade now. That little unit has seen some rough times, and cost me $25 back when. I use it for soldering, lighting my propane stove, lighting my charcoal chimney, lighting my smoking pipe and the occasional cigar, melting lead, melting the end of synthetic rope and string, igniting the ends of my handwarmer sticks, etc. I've easily run a gallon of butane or more through that little unit, and it still lights everytime on the first click.