Re: let me get my crystal ball out..
"... but can't afford to splash out £600 in one go."
Or just want to, even if they can afford the outlay. Thats one of the real habit of the modern age; pushing paying the bill back so it just doesn't feel as painful. I know an awful lot of people this fits, especially on mobiles. Its not so much the cost of a phone up front they can't stomach, but the 'extra' cost of an eye wateringly pricey one that is harder to justify.