I always had more than one for different reasons, after riding in the rain or in muddy conditions takes a couple of days for the shoes to dry and I need to ride the following day. Some shoes are easier to walk in, some easier(more efficient) to pedal (softer shoes vs stiffer shoe).
Also I use road and MTB cleats for different bikes.
Now I have 6 pairs:
3 road shoes with KEO cleats- two SIDIs, one Specialized
3 MTB shoes- two Bontrager and one Shimano winter shoe.