For guilt-free arts files, whether you’ve gotten digital files of my works from me or someone else …
Use the steps in the Proxri Deal to determine a reasonable expected minimum proxri for a period of time. Then you don’t have to worry. Of course you can add to your minimum later if needed.
Suggestion: For personal use, a minimum proxri of $0.99 USD per month, or $9.99 per year, might be a good starting point. Of course, everyone’s situation is different.