Dev, Prod, GitHub
Currently I develop web content on my local machine but for testing it I upload it to a live server which I rent. This means I do not have to maintain a local server on my machine. I use git on any significant project and push this to my GitHub account. In terms of back ups this means that my local machine and GitHub both have a full version history of the project. Also, the live webserver has the most recent live version.
For projects which take a lot of disc space, typically lots of photos, I can not upload these to GitHub due to their size restrictions. I therefore store these on usb sticks.
Currently I have a separate dev version of the project for implementing new features and any other significant change. If it works on dev I then implement it on the prod version and check to see if it works. If it does I commit it. I do not track the development branch with git. It is a good idea to frequently update the dev version from the prod version once any changes have been incorporated into prod.
I put a different favicon image in the dev branch eg colored red and also use css to make all the text red. This is so I know whether I am looking at dev or prod. It is easy to get muddled about that.