BoxRec

I notice champions taking their belts to the ring, and if they lose, the belt ishanded to the winner.
After a fighter retires he quite often is photographed with all the belts he has won. How does that work? Are there duplicates made for every title fight? Does a fighter normallyhave to defend a certain amount of times to keep the belt?
These things keep me awake at night!

Depends on the title & cost of belt.
Generally, the losing champ lends the belt for presentation/photos.
Couple of regional orgs require the new champ successfully defend 2 times before he's given a belt.
Australian National Boxing Federation awards a belt upon acquiring the title & another after each 3rd successful defence

i remember reading in kostya tzyu's book that he actually kept a title belt from the fighter he won it off(im pretty sure it was the first world title he won) he never gave that particular one back, but gave the replacement he was sent, back to the other guy. his thoughts were "I won THIS belt, so im keeping THIS belt."

What else could one expect from a Russki??

I remember when Gealy defended the IBO against Geard Ajetovic he forgot the belt at home and drove back to get it before the fight!! 8)

Oh that Gealy is such a nice guy isnt he.