I have a few kales growing in my raised bed and it keeps producing leaves and I keep consuming them. Do I keep doing this or is there a point where you would remove the plant and put a new seedling? Does kale lose nutrition value of the leaves after a certain point in time? I don't think so but was wondering since leaves are not growing as large as they used to and some of them have a different texture so was wondering
Most continuous production systems (tomatoes & peppers in greenhouses or the tropics being the major exception that comes to mind) do find it beneficial to replace old plants with young ones on a regular basis. In zone 4 we don't really have this problem, as winter provides a defined end point (you can pick kale in the snow, but it pretty much stops growing.)
Among other things, at some point (if left over winter around here, the following year) it will opt to go to seed, and flavor is generally not positively impacted by that - likewise the plant's production is aimed towards the seeds, not the leaves at that point.