It seems like it would depend on the number of projects and volume. If you imagine a paper kanban board in an office, they may be right that you don’t have one

It seems like it would depend on the number of projects and volume. If you imagine a paper kanban board in an office, they may be right that you don’t have one per project. Digital ones I typically think of (and use myself) as one per project. Depending on the system you may be able to filter and have the best of both. Tag the cards by project and filter when you want to see just that project. Unfilter when you want to see all projects at a glance. At some point it won’t scale, but that’s almost intentional. If you have too many cards on a board it is a signal you don’t have enough resources or have some other inefficiency that needs to be addressed. Also depends on your definition of “project”. Maybe a better phrase would be one board per -product-?