For what it’s worth, it used to be incorrect to pronounce the T in “often.” Not just stuffy or prissy, but plain flat-out incorrect. However, as literacy advanced with no corresponding advance in intelligence, the incorrect pronunciation with T became more common, and most dictionaries of the last few years recognize it as an alternative.
But the Editor recommends training yourself not to pronounce the T in “often” if you’re doing any public speaking. Why? Because it sends exactly the wrong message. It sounds like an obvious effort to be more correct than the common speaker, but it is in fact less correct than the pronunciation without the T. In other words, it draws attention to itself. You don’t want your audience thinking, “Here it goes—she’s going to say ‘off-ten’ again.” You want them to concentrate on what you’re telling them.