一般都说How long have you lived here?没有后面这种说法.因为live本身就是延续性动词,for用在这里是多余的.
How long do you want it for?
这里不能省略for,want是非延续性动词,所以要带上for.
也就是我们可以说 I have lived here for ten years.但不能说I have wanted it for ...,所以前者对时间提问可以不用for,后者要加上for,这种用法可以凭语感.对，for是表示延续时间段的介词
How long do you want it for?这里want不是跟for搭配，是How long do you want itfor?