This is a follow-up question to my previous one, What does Low/High mean on the connections of a chip?.
To create a HIGH connection, you often just connect the pin to VDD, which is often above VIH (and therefore sets it to HIGH). However, some people choose to add resistors to those pins, as shown below:
Credit: Wolfson
In this case, DVDD is 3.3V and the VIH is 0.7×DVDD. Looking at that, it seems that the resistors aren't necessary. What are these resistors for, and do I even need them?