@Ben_Aaronovitch You'd expect so.. Just found the series you're talking about.. thanks, I'd missed that. I'll go see if there is a logical reason other than plot.
@Ben_Aaronovitch Also: plot reasons. You have one less reason for any particular action: if you lose your only horse, that's a side quest at the least.. If you lose one horse in a pack train, just use the next one.
@Ben_Aaronovitch Local Economics? Horses cost serious money in these economies, so you'd want as few as possible (also; food, equipment, manoeuvrability ?)
@LegoAnkhMorpork @PaulKidby Dave Langford's column in the white dwarf.. Took me a while to track them down; totally worth it Those Kirby covers were magic...