I have a love hate relationship with tomato cages. I use the ones I have, wish I had more b/c they are so easy to use. but, they simply don't stand up under the weight of a tomato plant in full fruit, unless you stake them or tie them off to a fence. I find the most useful purpose for them is to lay them flat over a newly planted garden bed, to either keep chickens from digging in the bed, or to support a row cover over the top of them.
I will often put up a CP tomato trellis, then tie some cages to the far end of the CP to be able to put 2 more tomato plants in the row.