Martin wrote:However, when I've opened up and brushed out my Vario, I didn't find much and can't imagine detectable taste effects. My Mazzer Mini requires a brush out after each shot; but even with the Mini, I've never noticed a positive change after cleaning out the packed-in grounds around the burrs.

There's your answer. It's not a matter of the result of polling others (or reading HG One threads, etc) but what you can taste.

Au contraire. "Rely on 'what you can taste' is typically (for me, no offense meant, YMMV, ) pretty useless feedback, and I wish that folks would quit offering it. Sure, we need to pay attention to what we like, but I'm at a point where I'm enjoying some shots that I would have found unpalatable 15, 10, or even 5 years ago. In short, I've learned about taste.

My advice is that if you do or don't like a shot--can or can't tell a difference--check what others think, and only then make a decision to follow your taste or pay closer attention to what you might be missing. If I followed my taste, I'd still be posting requests for "chocolaty" blends to roast.

I follow some discussions on micro-subtleties of espresso (ex., tamping, retention, freezing, etc.) where the settled opinion and my own experience are roughly aligned. But sometimes when topics reemerge, I want to know if I'm in sync with the broader HB community or if I've missed something important. YMMV.