I wrote a while ago about my experiments to increase sulfate levels in my Rye IPA. My latest batch, with a sulfate level of 300 ppm, is far and away the best of the many batches of this recipe that I've made over the years. So, now what I need to do is brew it again, exactly the same way, to find out if the changes in sulfate were the reason or if I just had Ninkasi looking over my shoulder when I made the last batch. That's what I'm doing today...brewing exactly the same recipe, with exactly the same ingredients, down to the same bags of malt and hops. This is one of those things that can really increase your understanding of what impacts your beers, and it's also one of those things that many brewers are loath to do. I know that when I started brewing I wanted to experiment with different styles, ingredients and techniques and it was really difficult to get myself to brew the same thing twice. Fortunately, pretty early on I hit on some recipes I loved, so it was easier to justify rebrewing them since I wanted to have that beer around. But I guarantee you that brewing the same recipe over and over can be far from boring. Instead, I like to think of it as a challenge to my process and skill to see how close I can get to the last time I brewed the recipe. And since you'll likely be rebrewing a recipe you loved before, where's the downside? You get more of a beer you already know you like!