Do you have paying customers yet?
Before building it, did you talk to people to confirm they wanted it?
After paying everything it costs to serve one customer, do you make money?
How do customers reach you?
Did you hire or spend heavily before having steady customers?
How often do serious disagreements come up between the founders?
Which areas does your founding team cover?
Have you founded a company before?
How many people or companies could buy what you sell?
How many companies already offer something similar?
Right now, how hard is it to find investment in your sector?
These three numbers tell us how long you can keep going.