THE RESULTS: The key to these is making sure they're really, truly twisted tightly enough. When you feel like they're tight and it looks like they're gonna stay up, tighten some more. And a little more. When I first put 'em in, one of them fell shortly after I put the weight of the shoes on them — but when I added *even more* tension until I could barely twist anymore, they stayed.
Of course, YMMV: It works for me and I think it's worth a try, but I can't make any promises. The paint or wallpaper on your walls, the weight of your shoes, and your definition of "truly twisted tightly enough" can all have an effect on how well the tension rods hold up!
TOTAL COST: Each shower curtain tension rod was $12.87 at the time I bought 'em, but right now they're marked $13.23. Two tension rods (for two levels of shoes, including the ground) would be $26.46, and four (for three levels, like I tried) would be $52.92.
You could try this with cheaper, smaller curtain rods (like these, $11.83 for two or $16.83 for four), but they may or may not stay up, depending on how many shoes you try to load on 'em.