Vimes puffed on his cigar, held it for a moment, and exhaled. "You know, a few years back, my officers pitched in to get me a pocket watch. Beautiful thing it was, very well made, all with the finest clockwork." That was probably an odd way to reply, but there was a point to it, and he carried on.

"It'll keep going forever, clockwork, if you remember to wind it up now and then. But the funny thing about it- if you wind it up too tight, the spring breaks, and all that pent-up tension gets released. Usually right into the hand of whoever was winding it." His tone isn't accusatory in the slightest. He's being quite mild, in fact.

"Just a bit of advice, from one copper to another."