Client
The client's side
Requiring proof of work looks free. It is not, and three of the four costs appear on no invoice.
What You Are Buying, and What It Costs You
For the client: the requirement has a price, and three of its four components do not appear on any invoice.
Who You Lose by Requiring It
The requirement filters applicants, and the filter works against the people a client most wants to hire.
The Data You Now Hold
Screenshots of somebody else's machine are a holding with obligations, and most clients acquire them without noticing.
Reviewing Screenshots: Almost Nobody Does
The arrangement's value is assumed to come from the record. It comes from the requirement, and the record sits unread.
Alternatives That Answer the Same Question
Four arrangements that address what proof of work was meant to address, at lower cost to both parties.
Fixed Price Instead
The structure that removes the question entirely, what it requires of the client, and why it is avoided.
When Proof of Work Is Genuinely Right
The cases where the arrangement earns its cost, stated plainly, because a collection that only objects would be useless.