The vast majority of my punts (infact all of my early punts) were made on the day, which often meant seeing the best of whoever was available/picked up the phone when I had a window (sometimes the best of a bad bunch). I had a particularly bad punt not too long ago, which made me realise that a wasted window is better than a wasted wad of cash and feeling ripped off. And to minimise wasted windows, I've now started booking ahead when I know I will have an opportunity in a couple of days.