"Should I wait for and buy an arm64 Mac in 2020?" If you're developing for Mac, and macOS 11.0 will run on your 2015 Mac, then you should wait and buy an arm64

"Should I wait for and buy an arm64 Mac in 2020?" If you're developing for Mac, and macOS 11.0 will run on your 2015 Mac, then you should wait and buy an arm64 Mac in 2020. You'll need both your 2015 x86_64 and your 2020 arm64 for release testing. If you're developing for Mac, but macOS 11.0 will not run on your 2015 Mac, then you need to purchase both an x86_64 Mac and an arm64 Mac in 2020. If you're not developing for Mac, but you would like to help contribute to the Mac ecosystem by improving macOS/arm64 support for things, then you should wait and buy an arm64 Mac in 2020. You will be at the bleeding edge of Homebrew and CocoaPods and etc. and you will be required to make repairs to things that assume x86_64 or assume "stat DYLIB" or etc. You will be forced to use your old x86_64 device to get your actual task done sometimes, even though you'd like to use your new device. You will find bugs and issues with third-party toolkits that you depend on to get your job done. You will be expected to not only report issues but also to participate in fixing them. If none of the above apply, do not buy an arm64 Mac in 2020. Either now or later, buy either an x86_64 Mac or an x86_64 Windows. The Mac will be supported for several years. The Windows will be supported for however long PCs are supported. (Footnote: "in 2020" really should be translated to "within 3-6 months of whenever arm64 Macs are first sold to the public", not including the devkits.)