I'm reading "Right Ho, Jeeves" by P.G. Wodehouse and I've just encountered another phrase which I can't understand. Full sentence where this phrase is used (emphasis added by me):
In fact, not to put too fine a point upon it, I consider that of all the dashed silly, drivelling ideas I ever heard in my puff this is the most blithering and futile.
Best Answer
I never heard this expression before, and it doesn't seem to have much currency today (but see comments below - it's still known to some in the Midlands / north of Britain).
It seems pretty clear to me the meaning is in my life, and I'd guess puff in this sense means something like breath (i.e. - for all the time I've been alive and breathing.
I would not advise using the expression, since many people (not just OP!) will probably not understand it.