Research isn't just about finding new and unintuitive effects, its also about scientifically confirming and measuring what we know - or think we know - intuitively.

Why, did you knew beforehand what the most common "tipping point" was for collecting stuff?

If anything, 2 is quite surprising.

Think of the flip side: you have two of a thing. You have three options:

1. Eliminate one from your possession by selling, gifting or trashing it. 2. Just have two of a thing. 3. Get a third, and call it a collection.

The research implies that few people like option 2, and prefer option 3 to option 1.

After reading that, through a great deal of time and effort I discovered the corollary to that, which is people who own a first item are 50% more likely to acquire a second item.