I am always extremely forgetful when it comes to where I've put my phone.
Things have gotten so bad with me losing my phone (even if only for a minute) that when my family was in California, my sister felt obligated to buy me a little souveneir...
Yes, my sister bought me a little bell charm of a pig!
Pathetically enough, this thing has been a lifesaver.
Now I just need to shake my bag, hoodie, or jacket to see if my phone is there, rather than looking through every pocket imaginable.
(And trust me, I have a LOT of pockets.)
If you have the same problem, try a bell...
...It works wonders.