Nice one, using those quote marks. (I see what you did there.) Once and for all or Once and for all just wouldn’t put enough emphasis on how this time, it really is different.

You went for sincerity, but dipped into sarcasm, and ended up with a form that is very honest about smokers’ lack of commitment to quitting. Quote marks, taken off the page, made into air quotes, and slapped back onto the page.

‘On a scale of 0 to 10, I really want to quit smoking — “once and for all.”’