If you're looking for something, and you can't find it no matter how much you turned your place upside down, you have three options.
1. Give up – you lost it. Just forget about it.
2. Wait for winter time – the pockets of your coats will most likely contain stuff you forgot in there from last winter.
3. Move to a new place – packing is probably the best thing to do if your goal is to find something you lost.