Me: How long does it take to build a website?
Software Engineer: A couple of weeks.
Me: How long does it take to add a new feature?
Software Engineer: A couple of weeks.
Me: How about refactoring legacy code for our decade-old application?
Software Engineer: A couple of weeks.
Me: Just out of curiosity, how long would it take to build a replica of the Taj Mahal?
Software Engineer: Maybe a month. I don’t want to be too optimistic. That’s a bigger job and it’s like physical – not software – and I don’t know how to do that, so it would take longer, but it still wouldn’t be too bad.
Me: Got it. It’s good to have a sense of realism.
Reality
If a project is unscoped and takes longer than a day to code, there is no point in asking a software engineer how long it will take to develop something. It’s like asking how many pieces of candy are in a jar, but you can’t see how big the jar is or what kind of candy goes into it.
Accurate estimates are possible, but it comes after you figure out the size of the jar and the types of candy.