When you look at one of my delicate paper and wire mobiles I'm sure your first thought is never, "wow, that looks super durable - I bet that mobile will last forever!" People more likely wonder how long a mobile made of paper could possibly last. 
Some Very Old Mobiles
There are mobiles hanging around my home, and my parents' house that I made 12 years ago. Although some of them were made with aluminum wires (which dull with time), the mobiles themselves are in wonderful condition.
There is a Giant Summer Sky Paper Crane Mobile hanging in my living room right now that has endured 4 moves and years of children accidentally hitting it with balloons and balls (although they really shouldn't be playing with a ball inside the house). The birds have never torn or gotten crumpled in all this time. 
The poor mobile that I made for my daughter when she was born has gone through even more abuse than the one in the living room. Because my kids' bedroom ceiling was often lower than the living room ceiling, they have always been able to bump into this mobile very easily. The wires and birds in this mobile have gotten tangled repeatedly (at least once every other month) but the mobile still looks amazing after 5 moves, 10 years, and a lot of battering.
Although I don't recommend letting anyone hit your mobile with a ball or a balloon, these mobiles are really quite resilient. If they get hit or bumped they can absorb the blow because they move so freely. If a baby gets too close and pulls on an origami model, the mobile can stretch out to accommodate being yanked on. Now if the baby crushes the model in their little fist, that's another story.
Keep Out of Your Cat's Reach
I always recommend that these mobiles be hung out of reach of children and pets. My friend once took down a mobile that one of her children had yanked on because she was going to repair a model that had been damaged. My friend left the mobile unattended, and when she came back to it her cats had completely destroyed the mobile. :(
So as long as you take care of your mobile, and keep it high enough off the ground so curious kids and pets can't destroy it, your mobile should easily be able to decorate your home or work for many years to come.
