Image by msandersmusic from Pixabay

This is part of my Decluttering Toolbox.

The Diderot effect states that certain purchases will cause a flurry of follow-up purchases, called a consumption spiral.

For example, I’ll watch a movie trailer and say, “I have to go see that!” After I show the trailer to my wife, she’ll want to see the movie too. So we make it a date.

Two tickets only cost $18. It sounds like a cheap date, right? But we have to hire a babysitter. And if we’re going to get a babysitter, we should make the most of our time and go out to dinner. With dinner, I may want a flavored lemonade. It comes with free refills, after all! After dinner, I’ll be tempted by the dessert menu. At the theater, we might want popcorn and Red Vines, but then I have to get a drink. One thing leads to the next, just like in the children’s book If You Give a Mouse a Cookie.

What started as an $18 date ended up costing $90. And it all started when I watched a movie trailer.

A similar thing happened when a friend saw an ad for a gym and signed up for a 2-year membership. He bought Nike gym shoes, an Under Armour gym bag, a BlenderBottle Shaker Pro, whey protein powder, 5 pounds of frozen berries, and a Blendtec blender for post-workout smoothies. He also bought deodorant, shampoo, soap, and razors to keep in the gym bag.

But these consumption spirals pale in comparison to the one I fell into when I bought my first house.

Now, consumption spirals are not necessarily bad. Some are just part of life. When my wife and I had our first baby, we spent money on all sorts of things, e.g., furniture, diapers, and clothes. This is reasonable and expected. In fact, having a kid is an 18-year (or longer!) consumption spiral. And that’s OK.

So the goal isn’t to avoid all consumption spirals. Rather, we should be mindful of them. We need to think about what we’re getting into before we make that first purchase. Do I want to spend $90 on a date right now? Maybe I do, maybe I don’t. Either way, I consciously direct my spending.

In addition, when I enter a consumption spiral, I set limits, so they don’t careen out of control. Early in our marriage, my wife and I went out to dinner a lot, and I always ordered a flavored lemonade. (Strawberry is the best!) It was a good deal because I always got a refill. Or two. But these delicious drinks increased my bill and my waistline. As did the desserts. (Strawberry cheesecake, anyone?) These days, we order water with our meals and skip dessert. We also try to catch less-expensive matinees, and we skip the concessions.

Setting limits on how much we spend on dates means we have more money to go on more dates. And that’s the point: spend less on frivolous stuff, like strawberry lemonade, so we can spend more on what makes us happy.

Thanks to James Clear, whose blog post first introduced me to the concept of consumption spirals.