Most people try to maximize their productivity, at least in their own mind. But often they will get so focused on a project that it seems to drive them rather than the other way around. They'll apply more and more energy but the project just seems to get out of control or the desired completion gives way to scope creep.
If you are lost in one of these projects, you are doing yourself no favors by throwing more resources at it. Often, energetic entrepreneurs will continue because they believe they can force success with simple passion and hard work. Couple that hubris with a poor business model and more often than not you'll end up in massive failure. Even if the only resource you are expending is your own hard work and time, sometimes you just need to stop. Here are some tell tale signs you need to end this project and go do something else.
1. You can't get good data
The key to completing almost every difficult project is to have great information about the issue. Whether it's numbers you need, or more qualitative strategic insights, without clear knowledge around the problems you'll likely make it worse rather than make it better. Don't try and guess through trial and error unless you can really afford to take the loss if your attempts go sour. Better to stop right now and focus on how to get the insight you need to attack the project efficiently and effectively.
2. You can't get your head around the concept.
It's entirely possible this project is beyond the scope of your knowledge and talent. Flailing away at it with juvenile methods will not only move you closer to completion, it could make you look pretty stupid in front of people you need to respect you. If you find yourself drifting in and out of comprehension when working on the project, take a rest. You could just be fatigued. You can always come back and try again later. But if it still doesn't make sense, go find people who have a grasp on the project and get them to help you, or just transfer responsibility and move on. Better to have a slightly bruised ego than a companywide failure at your expense.
3. You can't articulate the project to those you need most.
Most major projects can't be accomplished solo. You need to coordinate smart people to cooperate and move in synch. If you can't figure out how to help them understand what needs to be done, you are heading for a big mess somewhere down the road. The moment you sense communication and process breaking down, you must take a step back and stop the assembly line before real damage takes place. The stoppage may cause a missed deadline, but a complete breakdown will likely do the same and have farther reaching implications.
4. The project is taking a toll on your health.
It's amazing how long it takes for some people to allow self-preservation to kick in. Many think it's a badge of honor to work themselves into a poor health state in the name of duty and ambition. Truthfully, no one likes to work with a martyr. If you are so involved that you can't get sleep or eat right, you need to reexamine the career choices you have made. People want to work with others who are in control of themselves, and can be fit, bright and energetic when tackling any project.
5. The project is negatively impacting key relationships.
If your spouse, son, or daughter, are expressing frustration that they don't know who you are anymore, you know it may be time to reevaluate the project you are attacking. If you set proper expectations at the beginning of a big undertaking those who love you can support you and help you through to the end. But the onus is on you to meet your commitments to those who are important. On the bright side, if you ignore them completely, at some point you'll have all the time you need to finish whatever you thought was so important.