I assure you - I will never play the Tarrasch again. If I remember correctly, it was advice from the old Russian school that said if you lose with an opening 3 times in a row, you should abandon it, because it will always have a negative connotation in your mind. I gave the Tarrasch more chances than that. I think my record with it in USCF tourney games was something like 1 win, 1 draw, and 9 losses or something outrageous like that. Maybe it was one or two more draws than that, but I remember that it was only one win in 10+ games, and the win was a tough fight against a kid rated 400 below me. That ship has sailed.

I play e4 as white, including several wild gambits, for open, tactical games. As black, I've gone back and forth between e5 and e6 as my main response to 1. e4 over the years, and I'm happy with that. Lately, I've been contemplating trying other responses to e4, mostly to learn more about them so I can face them better as white. The Caro Kann in particular has given me trouble as white, so I figured I'd learn a lot about it if I played it as black, and I'd be able to handle it better. That's actually why I started playing the French as black years ago, and that went from being the opening I hated seeing the most as white to my favorite opening to play against as white.

Actually, it was my black response to d4 that prompted this thread. I've been playing the Classical Dutch for the most part against 1. c4 and 1. d4 for a while now, with decent results. I'm just wondering if my lack of knowledge of more common openings might be hurting my overall development as a player. Should I try playing the Queen's Gambit Declined for a while, just because I don't know what it's all about? Or some Indian openings? I don't even know what the Indian openings are, other than that they all start with 1. d4 Nf6. I've heard names like Nimzo-Indian, Queen's Indian, King's Indian, etc, but I have no idea which is which. Is that a bad thing for a 1700 level player?

Our battles of yore, on this site, are no longer remembered, it seems.

Ken Smith used to strongly advocate playing open games and gambits until about expert in strength.  That advice may have helped him sell opening books but it always rang true to me.  Playing in this manner helps develop the tactics and attacking skill needed to improve at chess. Focus at becoming a tactical monster (including endings) and then broaden your depth with a variety of openings.

I also agree with RdC that a general knowledge of many openings is good general background.

And, of course, as Black you need to be prepared for openings besides 1. e4.

Do you think there are openings everyone should play at some point as part of their chess education? For instance, I always hear that newbies should stick to 1. e4 e5, from both sides. Do you think it's true? What other openings do you think everyone should learn at some point?

Or do you think that having an opening repertoire and just sticking with it long enough to know it really well is good enough, without worrying about any other specific opening that you didn't learn along the way?