Undertaking this project will require a lot of time and effort spent on activities that aren't enjoyable for their own sake, and there's a good chance I'll get frustrated and give up before actually completing the project. So it would be better not to bother; the benefits of successfully completing the project seem unlikely to be large enough to justify the delay and risk involved.

Would it be worthwhile if you could guarantee or nearly guarantee that you will not just give up? If so, finding a way to credibly precommit to yourself that you'll stay the course may help. Beeminder is an option; so is publicly announcing your project and a schedule among people whose opinion you personally care about. (I do not think LW counts for this. It's too big; the monkeysphere effect gets in the way)