Is there any canon information in Harry Potter that proves one way or another whether a wizard always owns only one wand as a matter of routine?
What I am talking about is a wizard buying and owning one wand and also a second wand (for backup, or simultaneous use, or separate purpose, or ceremonial+work wand), akin to people buying more than one pair of boots, guns or hammers.
A proof would be either canon info showing someone owning 2 wands simultaneously; or a statement showing why that does not happen except in rare exceptions (see below).
NOTE: I am discounting special situations such as winning an extra wand in a duel ala Harry (e.g. the second wand's obtainment wasn't intended/planned), or someone winning a Death Stick from prior owner (in which case it was intended as a replacement wand and not an extra one); or taking another's wand for a time being, ala Voldemort and Lucius Malfoy (since it was more of a "temporary replacement because main wand was useless for the purpose due to paired cores" - far from a normal situation).
Also, I meant wands intended for use - e.g. if Malfoy would have a (imagined by me) collection of rare antique wands, that's as irrelevant as someone having flintlocks in a display case.