Theydidthemath

If you like to nerd out about enough money to buy lunch at a counterserve restaurant then this is the post for you. If you don’t care about effectively paying $18 less on a $1200 purchase then this is not the post for you. The short answer to the title’s question is ‘Only in specific circumstances.’ Let’s suppose that we want to make some expensive online purchase and the merchant offers 0% APR financing to pay for the purchase over time, literally buy now, pay later. It could be via themselves, Affirm, or some other company. To make it concrete, let’s suppose that we need a new mattress which costs $1200. How should we pay for it in order to minimize its effective cost? ...

An update to a prior post about electric car efficiency using my relatively inefficient EV, a 2022 Audi Etron, as an example. We’ll include some up to date numbers and discuss DC fast charging prices as of July, 2025 (spoiler: fast charging is, indeed, expensive). See the prior post here for more context ...

I want to run some numbers on the energy used by our electric car that we purchased nearly two years ago. We’ll compare that to a roughly equivalent gasoline car. This is an interesting exercise because we bought what is considered a relatively inefficient EV. Let’s do some light arithmetic. ...