Let me start by saying that there are no hard rules about when to terminate a project but there are some guidelines that can help us decide when it's time to pull the plug. I had a chat with a friend of mine that already started and terminated many projects and he shared with me three interesting questions you can ask yourself when unsure about the future of your project:
1- Would you see yourself working on the project in 5-10 years?
Most entrepreneurial projects require a long-term commitment so you must be prepared to work on them for quite some time. If you don't see yourself working on it long-term it might mean that this one is not for you. Many successful entrepreneurs I spoke with in my podcast are people that are completely passioned about their business
2- Are you still learning something new?
You might not make money or get the reach you expect with your project but one thing that you must always be doing is to learn something new. One pro tip is to keep updating your CV every 6 months and check if you can add something new. If not it might mean that is time to let it go.
3- What do your co-founders/friends think?
If you are working on the project with a partner it's a great idea to speak with her/him and openly speak about your concerns. If you are working solo a great tip is to surround yourself with other entrepreneurs and use them as sparring partners.
I hope these questions help and let me know if you agree with them or if you have any other suggestions. If you want to hear the full conversation its available here
One thing is for sure if you are an entrepreneur most likely you will end up terminating one of your projects, and that is completely fine :)