Well I'm 76 so I guess for what ever I was due for a new phone anyway.  I think I had the other one for 4+ years.

With five in the house lost cells are a daily. We just call them and wait for the ring tone. Steve (CTR)

I lost my cell phone in the Mini a few years ago. It was in a case with a belt clip and a magnetic clasp on the cover. I searched the house and the Mini several times as well as the family vehicle.  I looked under the seats, everywhere on the floor, felling around with my hands where I could not see. Had to resort to buying a new cell.
Some time after, I was doing some work (carpets maybe) on the passenger side and, lo and behold, there was the cell phone stuck to the side of the floor cross-member by the magnet catch. It was held off the floor. so my hands did not find it when feeling around on the floor.

Are you under 70 years old? If so, you have no reason to keep your phone on your belt.

The shoulder strap in my classic tends to slip under the belt wallet for my cell phone.  You can guess what's next.  Flipped my phone off the belt when I got out.  Didn't notice it was gone and when I got back in the car and backed up.  You guessed it!!!!  Now I have a new cellphone.