Recurring expenses very often isn't necessary though.

For software the initial costs are big, but after that it can be pretty low maintenance or at least costing much less to develop new features when the foundation is set.

When you start to think about recurring expenses that's when you have to find a way to justify those expenses. And that is usually by adding bloat and unnecessary features that those that already bought it might not even want.

So now you have to pay for features that you don't want to keep using the features that you've already bought? Tough sell...