how to ensure the push of modification from local to GitHub always execute?

 Usually I only use the following commands to check in the change to github.

git add . //add the change in the staging area

git commit -m "commit"  //add the change to the local repository

git push //to check in the change to GitHub

Some times it is weird, I discovered that new files were check into the remote repository, the modified files still kept in the local repository.

It is better to use this command to check into the remote repository with force flag to ensure the change should be upload from local to remote repository.

git push --set-upstream origin master -f