Honestly you never will know. There is always a “what if”.
The simplest situation is when you run out of money.
The biggest challenge is knowing when way before your run out of money if something’s not working out quite right.
You get a nagging feeling that the same time and energy you have can be spent on other things to get a better return – whether it is on the next startup or another job.
The constraints that most entrepreneurs face tend to be masked by their bravado.
I hypothesize that the only time you know when it is time to shutdown and move on is when you no longer have a desire for the end state.
When you lose your passion.
If you still have the desire for the space you are in, and the problem you have chosen to solve, then overcoming all other odds is easier, because you still believe there is a wrong to be righted.
Most founders, though dont realize they have lost the desire for the space or the problem until much later. They are taught that persistence is the key to success, so the slog through the early warning signals.
How do you find out if you have lost passion for the space, earlier?
“Going through the motions” is one way to find out.
“Not getting excited to get up and go at it” is another way.
“Inability to acknowledge the small wins” is a third.
I can list many more.
The next part of the question is how do you know if this is “temporary loss of passion” or “permanent lack of desire” for your startup.
It is a permanent problem when your opportunity cost of doing something else is more than your current situation.