Before choosing a shower bench, decide whether someone will sit on it. This sounds obvious. Many drawings contain a large tiled rectangle whose eventual job is holding bottles.
Make the seated position real
Mock up the proposed seat on dry ground with a stable chair or suitable support. Check comfortable reach to the controls, hand shower, and products. Draw the shower door and the space in front of your knees. A seat positioned beyond easy reach of the water controls misses much of its purpose.
For someone with a mobility need, involve an appropriate accessibility professional in the complete layout. A seat by itself does not establish safe transfers, grip, or access.
Compare the space both ways
A permanent bench can integrate neatly with the tile composition and be ready without adjustment. In a compact ensuite, our taped bench footprint left less standing room than the owners expected once we added the door movement and their knees. A folding seat recovered space when stowed, but its brackets still projected from the wall. We marked those too. Folded away does not mean gone.
Schluter’s bench guidance describes integrated waterproofing at bench connections. For a folding product, obtain that manufacturer’s mounting, capacity, and waterproofing requirements before the walls close. Tile and a reassuring screw do not establish structural support.
Do not buy a seat to solve a shelf problem
On that bathroom, we selected the folding model before the wall work so its support and waterproofing could be coordinated. The client tried its operation and reach to the controls as part of the layout review. A bottle shelf was placed separately; the seat wasn't being asked to do both jobs. If nobody wants to sit, keep the standing area useful. If sitting matters, choose around that person's use before choosing a tile pattern.