Yes. You only need to add the upstream repo if you want to fetch the newest changes. So it is something that you will probably only run into on your second PR.

Yes. You only need to add the upstream repo if you want to fetch the newest changes. So it is something that you will probably only run into on your second PR. I wouldn't be surprised if the vast majority of GitHub users never send a second PR to a third-party projects. Probably the majority of users only contribute to their own (or their company's own) repos. Then a small number send at least one pull request to another user's repo. Fewer still would send more than one in a way that requires pulling new changes from upstream.