Do you calculate the per unit cost of fun activities or services?

We joined a pool this summer for the kids. It was really expensive, but it made sense when we signed up because the neighbors/friends belong to the pool and would be a chance for the kids to see their friends, among other reasons.

Anyway, my wife has logged the number of times we have gone (or the babysitter has brought them), and she’s calculated the cost per visit. Of course, it’s absurdly-expensive right now. So, she’s made a promise to herself to drag the kids there as much as possible before the end of the summer to bring the per-visit cost down.

I suppose I just don’t think this way. The x $ we spent for the season on the pool was purchased and that’s it. Done. We purchased the opportunity to go to the pool – not some number of visits.

But it did get me thinking of things that we own or services we pay for and how much we are really paying per visit/use/time, etc. For example, if I pay x$/month for smart phone, is there a way to calculate a per-day cost? How about a per-minute used cost? What about my home FIOS internet?

Anyway, i’m curious – does anyone else make these calculations (either formally in a spreadsheet, or informally in their head)?