When I moved in, there was one towel rod made of actual wood throughout the entire house. All other towel rods were made of 1/2" plastic pipe (safe for potable water, according to the printing on the pipe). Mostly, the rods are covered by towels, so I was never in a hurry to do anything about them.
In the picture above, you can see the wooden brackety gizmos that hold the towel rod to the wall, as well as the towel ring and toilet paper brackets (indistinguishable from the towel rod brackets, which makes sense given that one's a 28" rod, and one's a 6" springy rod, but both hang about the same distance from the wall. Also, the off-white pipe running across the sink, that was a towel rod, just 10 hours ago.
Even though I was in no hurry to get rid of the old rods and rings and whatnot, I'm glad to have replaced them. In one bathroom, anyway. The same stuff lives on in two other bathrooms.
I planned out where everything should go, based on how I have lived in that bathroom over the past several years. A little more room here, make that higher, now start drilling. Only after the towel bar and towel ring were anchored to the wall did I realize I wanted more space between the towel ring and the toilet paper. So everything moved. At that point, it was about midnight, and there's really no benefit in drilling through sheetrock at midnight - it will all be there in the morning. So this morning, I attacked it again, and I realized that the position that I had selected for the toilet paper had to change, too (which might have made the repositioning of the towel bar and towel ring unnecessary). Fortunately, I hadn't installed the toilet paper hanger yet, so it was less frustrating to change my mind.
You can see several spots behind the towels and whatnot, some of them are holes that I drilled in my indecision (looking like I've got a bad case of bathroom vampires, or somebody's been prospecting, digging holes, looking for oil, gold, or maybe the fabled veins of brushed nickel this bathroom's famous for). Some of the spots are the old sheetrock anchors from where the previous brackets were.
So, spackle and a putty knife are on my shopping list, next time I go to Home Depot.
If you look carefully at the first picture, you can see a sink drain assembly - I'm also going to replace the faucet, and I got started on that project, but the nuts holding the faucet to the sink are pretty snug, and way out of my comfortable reach. There's a bunch of tools that I could pick up at Home Depot, but if I need two pipe wrenches for this job, is it really worth it? Seems like I could hire somebody who has pipe wrenches and does this sort of thing for a living, and it might make more sense.