To take an example the people at the cafe in the next building over have a certain capacity to make food including heating in the over and all that. They don't take your order until the WIP drops below their threshold so they maintain their workflow without being overwhelmed.
Most of the time I have three "side projects" and I am really making progress on two of them and the third is aspirational... and that's OK! What's not OK is when you are starting new things over and over again and never finishing them.
https://en.wikipedia.org/wiki/Kanban
and
https://en.wikipedia.org/wiki/CONWIP
To take an example the people at the cafe in the next building over have a certain capacity to make food including heating in the over and all that. They don't take your order until the WIP drops below their threshold so they maintain their workflow without being overwhelmed.
Most of the time I have three "side projects" and I am really making progress on two of them and the third is aspirational... and that's OK! What's not OK is when you are starting new things over and over again and never finishing them.