Just as the name implies, push sticks are used to increase safety margins while guiding workpieces through powered table tools such as saws, planers, and routers. Do you need to use one? Absolutely - if you want to finish your work session with the same number of digits with which you began. 'Nuff said. Here are some good examples for your perusal:

The BEST Push Stick EVER!!! by Jay Bates


The Octo-Push (Part 1: Push Stick Templates) by hffcom


How To Make A Push Stick by John Heisz


Matt Makes a simple push stick by Matt Diresta


How To Make Push Sticks - A Simple, Cheap, & Easy Design by AskWoodMan


Make a Mudflap Girl Push Stick for Your Table Saw by Steve Carmichael