Being in control of technology is handy. You basically avoid Vendor lock-in. When the device breaks, the manufacturer can't ask excessive price for it's repair or for replacement parts - with User Controlled Technology you can repair it yourself and use generic parts. If you can't repair yourself for lack of skills, you can hand the technical documentation over to a professional repairing electronics and ask him to do it."
In the 1980s and 1990s, public, royalty-free standards were hailed as the best solution to vendor lock-in. The weakness of such standards was that if one software vendor achieved a dominant market share, embrace, extend, and extinguish (EEE) tactics could be used to render the standard obsolete.
Since the late nineties, the use of free/open source software (FOSS) has been pushed as a stronger solution. Because FOSS software can be modified and distributed by anyone, the availability of functionality cannot tie a user to one distributor."
So that Ronja is using the strongest knows solution against vendor lock-in. Ronja comes with a set of schematics, drawings, 3D models, and even some technical notes. The user can freely work with the source materials of Ronja, because they are designed using Free software tools.
Ronja is designed using stock general-purpose parts. No specialized one-purpose parts are used. If a part is stopped being manufactured, the developer can easily replace the part by an equivalent or similar one. If the developer fails to do it, the user can do it himself or ask someone generally skilled in electronics for helping him.