The initial OG reading will tell you a few things. First you'll see how close to the mark you came on expected OG. Second, you'll have an initial reading to compare to the final gravity. And this will tell you what the alcohol by volume (ABV) is. It's not necessary for a tasty beer. But as you get more into this hobby repeatability becomes more important and measurements help you achieve that.
In Vino Veritas, In Cervesio Felicitas Anonymous
Gotcha. I have a lot of equipment but don't have hydrometer. I will have to get one. But glad I don't need at the moment. The local brew supply is open tomorrow but I plan on being well into it before they open. I got an extract IPA kit. I'm ready to be hooked! Lol been thinking about doing it for a while but never truly pursued. Now I'm ready.