[Alex3917]

Best practice is to follow the example of the subway system and build short spurs at the end of each line in the directions you might want to continue expanding. That way you're not incurring any real additional cost upfront, but you're saving a ton of money in the future if you decide to keep expanding.

Don't do work before you need it, but also don't give up optionality unless you're getting commensurate benefits from doing so.