Disagree with Telegraph here.
Don't burn through Earth's resources to dangerously low levels, THEN start exploring. Explore WHILE using Earth's resources. If you wait until you are almost out of something before you explore, you may not be able to build something you need!
Same with all other references to resources at dangerously low levels.
An example to prove my point:
I had a game where the Sol system did not have a critical mineral, except in trace quantities (<10000), and except on Earth of course (and Earth was low from the start). I want to say it was something as important as Duranium, but not actually Duranium. As a result, construction of various facilities (specifically MINES!) ground to a halt until I found another source two jumps away. I was also unable to build ships that required the mineral. For a brief time, I had only the ships I had on hand. For a MUCH longer time, I had to wait for mining of the mineral to get to a sustainable level where production wasn't halted every few months because the last shipment had run out.
Never let yourself get to extremely low levels without exploring, or you might face worse than I did. If I hadn't been exploring, I might have gotten actually stuck.
It's actually lucky I found that planet. It was extremely rich in the mineral, and its immediate neighbor also had a fairly rich supply. Too bad the extremely rich one was uninhabitable...