It depends on what it is... earlier this year I deliberately held out some fabric. Have been looking for 3 months now, really looking. Two pieces, can't find anywhere but I know I saved them.
After I look at the usual places, then I consider other ideas... When I put things in "safe places" they can disappear for years.
And then the day after you've given up and re-bought whatever it is, I will open a closet that has been opened many times before and stuff will fall on your head. But only after you've paid for the replacement!