If the project is done the potential on this is continuing residual income for both of us.
Can you give more detail about what you mean by backup your projects?
This question is super vague... I can tell you about backup software, and backup systems if you are just looking to backup your work so you don't lose it in a disaster.
I just am not sure that is what you mean seeing as you seem to want to share income with whomever helps you on this.