No, it’s bad business because it doesn’t scale. Software is lucrative because you make it once and sell it to thousands of customers. If you’re making every customer their own bespoke thing, you’ll spend all your time for little return.

“Billed to the customer” means you’re charging the customer by the hour / project. You can get plenty of return selling bespoke things this way. Accenture is a $200 billion company.

That’s called Professional Services. Professional Services assemble a solution for a customer from a variety of components and maybe build some glue or the equivalent of a dashboard. This is not the same as having a ton of “if” statements in code to handle customer X vs customer Y.

The secret, as a software vendor, is to generalise these bespoke customer requests so you can sell the solution to all your customers (and get more customers!). If you are really cheeky, you can even get that customer to help fund the development that will make your business more money (hey, it’s win-win). You need to ruthlessly follow this approach though, as the rot of bespoke code will quickly become an insurmountable quality nightmare that can sink your business.