Five days is a ‘just right’ length of time for making a breakthrough on a difficult problem.
Here are some other innovation methods people use for problem solving, and some difficulties with them.
Strengths and weaknesses
Strengths: Very quick, easy to convene. Weaknesses: Hard to learn more than one or two takeaways, tends to involve more presenting, less participation hard to do any actual thinking, let alone doing.
Strengths: Quick, quite easy to convene, some time to think and open out a problem. Weaknesses: Similar to half-day workshops, you can open up an issue, but hard to close it down and make decisions.