>>>But "been frequenting" is past, right?
>>
>>No, "I have been frequenting" suggests that I'm still doing it, you see.
>>"I frequented that club in my twenties" is in the past
>
>This is the shift that I quite often don't get - "I have been frequenting" sounds like past to me.

Is that because other euro lang's use the "I have verbed" construct to denote a one-off action/happening?

e.g. in French "J'ai parle avec lui" (I have spoken with him) = "I spoke to him"
     in German "Ich habe mit Ihm gesprochen"

In your above case you're even making it more complex by using the continuous. If you'd said "I've frequented the place for years" it'd suggest that it's something you do regularly, and continue to do so. Not a lot of difference really.

If you said "I frequented the place for years" or "I used to frequent ..." it suggests something you don't do (or aren't doing) anymore -the imperfect tense (don't ask me how perfection comes into it)

"I had frequented ..." - something I used to do before the time to which I'm referring: "Last week I visited the museum. I had not visited it for years"

>
>>>OK, you found me :). Tull fan (albeit not of the rotating ventilating persuasion) for decades.
>>
>>Oh, I already knew that :-) BTW, "fan" is short for "fanatic", so not the sane word as the ventillating device.
>
>I already knew that. My previous machine was a fan club. It had four fans (two in the power supply, one for the CPU and one more for another hot chip.