What licence should I sell my cut files under?

Three tiers is what most of us settle on, and it's what this site's shop uses:

• Personal — make it for yourself and as gifts. No selling the finished item.
• Commercial — sell finished physical items you make from the file, unlimited quantity, but you may not redistribute or resell the file itself.
• Extended — commercial plus the right to use it in your own product designs or teaching materials. Priced 3–5× personal.

The line that matters and that people forget to write down: the file itself is never resellable, ever, at any tier. Say it explicitly in the listing, because "commercial use" reads to some buyers as "I can put it on my own shop".

I also add a plain-English summary at the top of the licence file. Nobody reads legalese. Two bullet points of "yes you can" and "no you can't" prevents 90% of support emails.

Worth stating the jurisdiction and putting the licence inside the download as a text file, not just on the listing page. When there's a dispute six months later, what shipped with the file is what counts.

Rewrote all my listings with the three tiers and a plain-English box. Support emails down noticeably. Thanks all.