Every idea is not worth pursuing. Even good ideas may not be worth pursuing. And sometimes, even mediocre ideas are worth pursuing.
If you’re thinking in terms of odds of success, you might be going about it the wrong way. It’s very difficult to realistically assess the odds of success. If you are in love with an idea, every data point will scream, “this is going to work!”. On the other hand, if you are only surveying the landscape for a sure thing, no matter what it is, you might end up pursuing something with good data behind it, but for which you have no particular passion or special skill. Neither are great recipes for success.
So if the odds of success, the level of love you have for the project, or the “goodness” of the idea are not sufficient metrics for deciding whether or not to act, what is? Tolerance for failure.
Only go after an idea that you are willing to fail at it. There is always a chance of failure. If you can imagine pursuing something and failing, and it doesn’t feel that bad, do it. If you know you’d be happier to have “loved and lost” on your idea than never to have attempted, do it. If, on the other hand, you think failing at something sounds worse than never trying it, it’s a good sign that it’s not a project worth your effort. If your main worry is over the chance of failure, rather than the discomfort of not attempting, it’s not a good fit.