Never 8. My M1 Max has 64GB and there's a world of difference between it and the M1 Pro with 16GB furnished to me by the client.

The 16GB machine must be restarted every other day or so without fail.

The 64? Usually when there's a software update that requires it.

One other think to keep in mind for developers is the need for extra RAM should you ever need Docker , to run a server VM, or need to run a VM with a previous version of Xcode/macOS.