>>2125675
I only do so when the labor is more expensive than the replacement goods. This chart is already outdated but it still holds up imo.
I also heard some people switch them regardless of peasants/cost on government owned buildings if the required goods are produced by privatized buildings. This is more efficient in a sense that profits that would have been otherwise deleted now get added to the investment pool. But for me it's just easier to get them privatized so I don't have to fiddle with them for few hundreds pounds in the IP.