We have the tomato cages that you buy from Home Depot and Walmart with the three legs on them you punch into the ground.
No matter what size you buy even the biggest... they are never tall enough.
EMT or electrical metal tubing... basically 1/2" metal conduit is cut off with a grinder three or four feet long and driven into the ground in a triangle pattern around the plants... three pieces. Sticks out of the ground 2 feet or 3 feet depending on the variety of the Tomato we are growing. The top of the three EMTs is level and even. Then I put the tomato cage legs inside of the conduit. Now my tomato cage is 5 to 7 feet tall at the top.
We have had cherry tomatoes that went 10 ft tall but I never bothered beyond seven.
If the cages are get overloaded and I start to worry about them I drive another piece of conduit 6 or 7 feet long beside them and wire tie it to the cage for stability.
Clever and thanks for that. One of the things I do like about the circular cage type is that they are stackable when being stored. 18 of them stacked in 6 apiece only takes up a footprint of maybe 4' under the deck.
