Sunk costs
Yesterday my mum took my daughter shopping to get some tap shoes. She started a dance class at the start of this year and this coming semester they are going to do tap dancing as part of it. They weren't cheap. There is a risk (likelihood?) that in six months time they won't fit or she decides she doesn't even like tap dancing. At that point they appear to be a sunk cost. But what fun would it be without them, right?
She wore them the whole day yesterday. Last night she put on a long winded concert and practised auditioning for the voice (maybe Australia's got talent would be a better choice if she ends up being any good at the dancing). Regardless of where she ends up in six months time, they're going to enrich her experience, and that's what childhood is all about. There's no such thing as sunk costs when it comes to positive childhood experiences.
Likewise, there's no such thing as sunk costs in personal learning and development. I've had to come to terms with this with the whole PhD thing. I often feel judged by others about my decision to pursue a PhD. I know a lot of people think it's a waste of taxpayers money to fund people to look at issues unless they are going to contribute an outcome that betters society. But they miss the point about the learning experience that individual undertakes. That people who are committed to lifelong learning and invest in personal development make society better. I think that's one of the best outcomes we could hope for.