Having to delete binaries before changes occur?

I’ve been having a problem recently where to get any c++ changes to apply to my project I have to delete the binary folder, rebuild and then re-generate the visual studio files. Does anyone know why this could be happening?

You need to rebuild your project from IDE (ie Visual Studio) every time you edit C++ code.
C++ and blueprints are very different. C++ is a compiled language and foremost should be converted to binary code to be executed. Blueprints are like Interpreted Languages and they don’t get converted to binary.
Converting to binary is a complicated process that has many steps that are performed during the building process.
In case you really don’t like rebuilding your project unreal engine has a live-coding feature that allows you not to rebuild your game after changing C++ code but it’s still experimental and unreliable. You’ll need to rebuild from IDE if you’re editing .h files or constructors’ code.

Did you update VS recently?
It could be a bug in a newer VS Versio since I saw multiple complains about this problem in the forum lately.
Someone seems to have found a solution for the same problem, i recommend to check out his solution:

Usually closing the editor, building and reopening fixes it for me.