The goal of reducing e-waste is commendable. I really like the idea that if people built their own toaster then they will know how it works and they will feel more comfortable repairing it if something goes wrong with it.

That being said I would have started a project like this with researching why toasters end up in the trash. Is it because they break? (and if so which part?) Or is it because people get bored with the old design and want something new which fits their kitchen decoration better?

My suspicion is that there are garbage toasters not built to last. And then there are good quality toasters where the toaster probably could serve for decades. Maybe even hundreds of years with part replacements. But changes of taste, and design is what limits the lifetime of the second kind of toasters in reality not breakage.