Staying with a difficult problem is sometimes necessary. At other times, continued effort repeats the same unproductive move. A break is more useful when it is a deliberate part of the work rather than an escape from an undefined task.
Capture the state before leaving
Write what you are trying to solve, what you have attempted and where the uncertainty remains. Include the next question you want to answer. This reduces the cost of returning and makes the unresolved issue more precise.
For a design problem, save the alternatives and the reason each one falls short. For a technical problem, record the failing behaviour and the evidence already collected.
Change the kind of attention
Step away from the exact interface or document you have been staring at. A walk, a different task or rest may help you return with a different perspective. There is no universal interval that guarantees a creative breakthrough.
A break cannot replace missing research or a decision someone is avoiding. If the obstacle is an unanswered requirement, arrange the conversation that will resolve it.
Return with a different question
Instead of repeating the same attempt, ask what assumption has remained fixed. Could the problem be smaller? Is the proposed solution addressing the wrong cause? What would a simpler version need to do?
Keep the evidence
Compare the new approach with the actual requirements. A fresh idea can feel compelling because it is new. The work is still to establish whether it fits. Use the break to improve the quality of the next attempt, not as proof that the next idea must be right.