The Lindy effect says that for anything that does not wear out, like a habit or an idea, the longer it has already lasted, the longer it will probably keep going. A habit people have kept for 3,000 years has proven it meets a deep human need.
Each entry below gives a behaviour, roughly how long people have done it, and why they keep doing it. Where it fits, it names a well-known business built on that behaviour. Ages are approximate and written from memory, so check any date before you quote it.
1. Going to the market — at least 5,000 years. Every ancient town had a central market where anyone could buy or sell. Amazon and eBay are the same market, moved online.
2. Bargaining over price — as old as trade. In most of the world's markets, the first price is only the start of a conversation. eBay's "make an offer" button keeps this habit alive.