See my response here.
But also while I’m here, here’s another example from just normal daily life: travel booking. When I used to go places I very often had a folder full of travel emails in my inbox but I didn’t bother making a folder in my file system. But then sometimes I did. So I might have had:
Email? | File system? | |
---|---|---|
16.01 First trip | ||
16.02 2nd… | ||
16.03 3rd… | ||
16.04 4th… |
So yeah, for some people an index might not be absolutely required but you’ll just need to be careful.