In Water Bath Canning sterilizing jars is not needed PROVIDED processing time is more than 10 minutes. Most recipes call for at least 10 minutes processing time or more.
You don't need to sterilize for pressure canning. Everything will be well sterilized by the high heat involved in pressure processing.
You must however start with clean jars so be sure and always wash your jars before you do any type of canning. I am assuming you would know that all equipment needs to be clean before any canning.
I don't personally use any recipes that call for less than 10 minutes, I am at high altitude and everything has time added.
If you do have a recipe that calls for less than 10 minutes you might consider adding time to your processing. This way you can simply skip this step. It is up to you.
Go ahead and check your recipe, does it call for less than 10 minutes processing time? Don't forget to figure you altitude. If so you should be sterilizing first. Here's how:
|Canning Methods - which one to choose?
Step by step: Pressure Canning
Step by Step: Water Bath Canning
Sterilizing Canning Jars