It comes down to unknown unknowns. Should I poll my supervisor/co-worker about every problem to see if there is already a solution? As the new guy, I have no id

It comes down to unknown unknowns. Should I poll my supervisor/co-worker about every problem to see if there is already a solution? As the new guy, I have no idea who or what I should poll people about. The second problem is that people will keep stuff hidden. Have that sweet script that creates 1000 users for testing? You might share it with the team, you might also think its too trivial to bother sharing. That being said, I can see how it can be frustrating. We have packages upon packages of existing functionality, languishing somewhere in source control, used maybe only once. In the meantime, someone is going through the cycle, not only of ignoring what someone put on gitub, but what has already been tested and qa'd by their own company.