Sometimes, people misplace the owner's manual that came with the car, so it's important to find resources where you can either access the same information online or request a new printed copy of that manual.
It's not uncommon to misplace manuals between the time you first purchase a new appliance and the time you need to look up something about it after you've owned it for a while.
The second category consists of those who frequently misplace their sunglasses, so they can't see spending big bucks on something they might never see again.
Patterns have a way of getting lost, and this way you will not only have an extra if you need it, you will be able to find your pattern again if you happen to misplace both copies.
It's not unusual to misplace the owner's manual that comes with small appliances between the time of purchase and when you actually need to use them.