Sorry, I beg to differ. [LTSCALE]

I use it all the time. Yes, it does affect the whole dwg. but that's teh idea, that you can scale the line type to 'look good' for what ever 'scale' teh dwg might be in. Either in Model space or in Paper space. Most 2d stuff can be accomplised in model space anyways, with paper space (or 'layout' as it's now called) being a bit of a hindrance.

While Acad does come with a lengthly list of line types, and there are methods for creating your own linetypes, most 'amatuers' will use only a few. it's easy. Not really any need to know ANSI standard linetypes, and line weights..

Untill they learn a bit more with ACAD, ltscale is an easy way to view what they intend.. and if it's a quick 'view' of any file, changing he LT scale can and will render quick results to see if different line types have been used..

Yes, teh proper way is to set it up before you begin, but he has imported / opened a DXF. Ideally, he should be pulling the DXF apart, and placing he appropriate elemets on the right layer.

Again, I will agree that being trained on ACAD is teh best way to go. it is a complex program, that has definitley improved and evolved over the years. There are many ways to do what you want; some right, some not-so-right. and many fall into the trap that since they have Acad, they can draft up plans & such.. it's just a tool, a fancy pen and paper..