Is the hand held going to be the only shower head? Then get a sliding bar and be sure to situate it high enough that someone 6’4” or so does not get whacked every time they shower. If this is the second or third shower head, you have choices.
I have 3 heads in my 3x5 shower; a wall head on the side wall, a big rain head from the ceiling in the center of the shower, and the hand held. I use the last two every shower. If I am deep conditioning my hair, I appreciate being able to put it on the bar and adjust it so I can sit on a stool, bend so I do not get all wet, and use both hands in my hair while the water is pointed just right to keep the rest of me dry. If I am using it just to rinse my body, the single wall holder works well for me. Think about how busy you want the wall to look and whether you might sometimes use the hand-held as a body spray, too. In that case, you will want the sliding bar on the side wall. Here is my very busy handicapped shower.
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