I don't know about you, but I have been the recipient of the "five minute favour." As Adam Grant says in the below article, it can be like a "microloan of your time, skills or network".  Things as easy as answering that question from one of your connections or connecting two people in your network can make a big difference.  I have found that people remember those favours and are more than happy help you out as well.  Bottom line, it is never too early to give back.