Hi,

Yes you are right and it's up to you but this info will help.

If you use a simple arduino structure with all sources in the project folder being part of your project then you are right the .sln and .vcx... files are not important. However, the selected board and serial port are stored in the vcxproj

If you use sub folders for your source code and include/exclude certain sources into the project. Or use linked/shared sources between multiple projects then you will want to keep the vcproj.

The .sln simply holds a list of paths for vcxproj files (projects) and also, annoyingly, stores debugger breakpoints.

The .vsarduino.h in the _vm folder can also be ignored. The xml files in the _vm folder store the project settings such as extra defines, compiler switches, debugger settings that you have added manually. If you haven't changed any of the defaults then the files have no use. If you are using the debugger the xml files also keep track of the what the settings were after the last upload.

Vs creates some files/folders sometimes and they can be ignored.

The Release/debug folders can be ignored unless, as you say, you want to keep versions of previous binaries.