We bought the bookstore three years ago in August. Maybe there is some light at the end of the tunnel, if you squint at the numbers in a certain way.

Things have been changing a bit around the bookstore, as we mark our third birthday. A retrospective is in order, in four parts.

Donations are the lifeblood of this literary micro-business. We take anything dropped off at the store and we occasionally do pickups for people who live nearby. We filter for the books that are in good enough condition to sell, which we then process and put on the shelves.

We did a survey in August, September and October to find out more about who visits our store.

We have been looking recently at the question of what types of books sell best. We have no shortage of hypotheses. But the number of potential variables make it hard to do the analysis, let alone find any general guide.

Now we think we might have found one useful rule.

In June we made 322 sales for a total revenue (including GST to make the numbers relatable) of $8,522. This means the average sale was $26.50, a bit above our usual of around 23 dollars. (Basically people usually buy about two books and they cost about 12 bucks each.)

The bookstore generates a lot of data. Amongst other things, we know sales numbers, revenue, what kinds of books we sold, and how much each customer spent, as well as social media interaction, traffic to the website and the number of subscribers to our excellent podcast, Ears Wide Open.

December is the best month of the year for revenue at the Open Book. December 2017 was our best month ever and we made $11,000 (!), about 60 per cent more than October or November. Breakeven at the moment (with me donating two days a week to the store) is around $7,500.

In September we made 274 sales. In November it was 268, practically the same. But revenue was over $1,000 more in November than September. The difference was in average spend per customer, which we call basket value.