Why do we have variable parts in the module?

In the interface we show the option to choose "accessories". Why would we need these loose parts? For some jobs the handyman needs a specific size of bit. For instance, during an interview a handyman told us that every extractor hood needs a specific size whole for the tubes, according to the design of the hood.

If we would add every size bit into the module, the module would become unnecessary big and heavy. It also does not make sense to make separate sets for every (group of) bits, because the tools going with these bits can become very expensive. By having a predefined set, that only needs the variable parts to be added, we can make sure the handyman has the tools he needs, without taking up too much space or making it extremely expensive.

For further development it would be interesting to look into how these variable parts are found and added to the module when picking up tools. It is also interesting to look at how they are added to the module: are the clicked on top? Or are they put inside?