Should I start measuring my efficiency? And what exactly is it.

What are the advantages/process/and what exactly is the efficiency? Never really paid that much attention to it. I kinda have a guess at what it is but not 100% on it

Efficiency explained here.

The reason you migh be concerned with efficiency is that the better the efficiency, the less grain you will use in the long run.

Aight thanks...i understand it now...i will be measuring it with my next batch. Thats going in my favorites

Plus, if you have a recipe which is designed for 75% efficiency (if the recipe doesn't state the efficiency it is designed for, this is a good estimate - most recipes published in BYO and Zymurgy assume this if I remember correctly) and get only 60%, you will get less extract, and therefore lower SG. With that lower SG, if you add your original hop schedule, you will end up with an overhoppped beer. The reverse is true as well. I started using my own grain mill and started getting efficiency in the 80s. Before I had modified my grain bills to compensate, I had higher SGs than I expected and my hop additions were not high enough to match.

If you have the first problem, you can compensate for a lower than expected efficiency by supplememting with DME. It is always a good idea to have a pound or two handy for this reason.

But, the key is you have to measure your efficiency first to know if you hit your target or not.

I think consistency is more important that the actual number. If you are all over the place 60-80%, it's tough to tell what to plan for. But if you are consistently hitting 65%, then you know what to expect, and your beer will reflect that.