Having recently compared two lunch companions to each other in point of having checkered pasts, but aware of recent shifts in the meaning of the phrase, and not wishing to give offense, I quizzed one of them on the meaning of 'has a checkered past' as applied to a woman and to a man. He replied that it suggests that the woman was a prostitute and the man a crook.
That answer is not wrong and accords with current usage. If you listen carefully to how 'checkered past,' 'checkered career,' and similar expressions are now used, I think you will find that they are often used with a pejorative connotation. But the phrase originally had no such negative connotation as far as I can tell. My old Webster's defines checker, v.t., as to vary with contrasting elements or situations and gives the example of a checkered career as a racer. Nothing pejorative about that: the racer's career had its ups and downs. Or one might describe a man whose 20s were spent in the Jesuits, his 30s teaching philosophy, his 40s as a soldier of fortune, and his 50's as an exterminator of insects as having had a checkered past. Nothing pejorative about that either.
Only a liberal or an idiot thinks that change qua change is good. And so I hold to the old way of using 'checkered past.' But I can do so only if my language mates let me. Like it or not, meaning is tied to use. If the phrase comes to be used in an exclusively pejorative way, then I must conform to the change if I want to communicate with the vulgar as opposed to display my erudition among the learned.
It is too bad that we are at the mercy of the masses in so many things, though not in all things. I have no objection to the phrase 'male chauvinism.' But if enough come to substitute 'chauvinism' for it, then the former has been rendered redundant and the latter destroyed. And that would be a change for the worse. I suppose this makes me a limited prescriptivist in matters linguistic.
For more on this particular example, see Chauvinism and Male Chauvinism.
Addendum. And then there's 'hook up.' To members of my generation it does not imply an exchange of bodily fluids when used in a sentence like 'I hooked up with Sally again after years and years.' Peter Geach, an English philosopher of my father's generation, in one of his books uses 'make love' to mean something like 'woo' or 'make a romantic approach,' a quaint usage that had fallen into desuetude by the time my generation came of age, a usage to be replaced in the main by one rather more raw and 'hydraulic.'