The cost of adding a feature isn't just the time it takes to code it. The cost also includes the addition of an obstacle to future expansion. The trick is to pick the features that don't fight each other.
“My work begun to spread out. And calls to the universities begun to take me out of my garden, you know.”
“Children simply don't make the distinction; a book is either good or bad. And some of the books they think are good are very, very bad indeed.”