Inexperienced design thinkers often believe that detailing is easy; that it is simply filling in the blanks and running a test. Reality bites, however, and experienced designers and design teams plan considerable time for delivering and documenting their designs. Why does it take so much time?

First of all: detailing isn't easy and can be considered a design project on its own. Some ‘details’ require a lot of dedicated design activities and meetings. For example, creating the small explanation boards for an exhibition is indeed just a detail, but in order to gather all necessary information, write copy, and have it reviewed can easily take up weeks where there is a lot of interaction with others.

Second, unexpected can problems arise that may halt the entire project. Some problems existed already but you were simply unaware of them, such as recent changes in regulations. Or, technical issues that disable specific ideas you had. A developer of professional printers developed a groundbreaking technology but discovered the hard way that the resulting product dimensions were too large for elevator transportation. Which limited the placement of the product to ground-level locations.  Some problems are enacted by previous design choices. For example, if you decide to develop an application to make an exhibition more interactive for visitors, you may end up dealing with numerous new problems, like privacy issues. 

Third, building and testing functional prototypes requires ample time, but managing all proposed changes can become a nightmare. A simple test with few users can result in dozens of proposed changes. Each of them needs to be evaluated, requires an improved design, adapted documentation, and must be built, integrated, and tested. In software development, there are dedicated roles and processes for this ‘release management’.