Welding Tips and Tricks

I've just started using TIG and I've noticed that lanthanated electrodes come in various percentages.. Mainly 1.5% and 2%. Is there any rule as to which one to use. I'm primarily welding 1/8" steel, but also do some aluminum.

I wouldn't say as there is a particular rule, so much as personal preference. I use 2% alloys for my tungste, but frankly, the difference is rather nominal.