One of the options for students enrolling into Hogwarts, if they come from a wizarding family, is that they have the option of using a hand-me-down wand. But short of wands being damaged beyond repair, we don’t see many people replacing them, even though it happens enough that hand-me-downs are a valid option for new students.
So how long does one last? Does a wizard normally use one wand in their lifetime, or is it the kind of thing where an old, worn-out wand is fine for schoolwork, but you’d need something newer/better for adult life?
We know that wands choose their owner, and can change allegiance.
Perhaps if a wand rejects (or is won from) it’s owner, it can become a hand-me-down.
Also, witches/wizards die. At which point the wand can be a hand-me-down.
It might also be that the perfect wand is too expensive, so the witch/wizard buys a cheaper “good enough” wand to get through school, then decides to treat themselves later when they have more money.
Perhaps a family has a cheap wand for their kids first year(s) at school incase they break the wand. When they get older, they get a “proper” wand and the cheap wand can go to the next kid.
I’d imagine that families would share these hand-me-down wands with other new families, similar to cots/prams/clothes etc.