I've been experimenting with various amounts of memory from 8 to 128 GB with both Windows and MacOS. While 8 GB of RAM is only enough for light tasks in the browser - 16 GB is pretty much the minimum for work.
Since I'm working with Web, API and Mobile applications, I want to quicly jump through them on-the-fly while developing. I'm also using Photoshop once in a while to edit various assets for applications. Here I think 32 GB is mandatory, unless you don't need great performance and in the same time want to reduce your SSD life-time with Memory Caching to disk.
While also running both Windows and Linux VMs to test native applications for those platforms 64 GB begins to be just enough and I saw OS was swapping a lot to the disk.
While also running 2 VMs (each with 16 GB memory) - 128 GB starting to be just enough...
Are you heavily multi-task'ink? How much RAM do you have? Would be awesome to hear about your workflow.