These paid thieves come and go mysteriously every second or third year.

这些付钱的小偷每隔两年或三年就神秘地来来去去。

Now it was a show-piece of a quality so rare that Toby, who normally changed his dwelling-place (one could hardly say his home) every second year, had refused all offers for it for several years now.

现在，这是一件品质如此罕见的展品，以至于托比通常每两年更换一次住所（很难说是他的家），现在已经拒绝了几年的所有报价。