I have a friend the redecorates her bathroom at least once a year- new shower curtain, towel set, bathmat, toilet cover, etc. She donates that other stuff. I think she is nuts.
I have a set of "nice towels" that I hang up if I am going to have company. Actually there are a couple of sets of these since I have some holiday themed ones specifically. We actually USE the bath towels that may or may not match. I have gotten some from thrift stores, some from people that were moving or upgrading or whatnot.
I cut up towels that start to tear or have a seam coming out or sometimes some of them have a weird band near the bottom edge that gets weirdly puckered if dried too many times. (I really don't like that).
So that's the pecking order in my house..
Guest towels then
everyday use towels then
I have been thinking about this lately because I love those super fluffy towels that nice hotels have.. and those are so not the towels I actually use in my house..
Sheet sets I will use until torn but any stains would NEVER go on a guest bed... I HAVE been known to match up two sheets that were not actually part of the original set (a white and green striped fitted sheet with a white flat sheet that are not the same brand for example) because one or the other got torn..
I do not use bathmats. My cats like to mess with them too much.
I wash my shower curtains in the washer, but if they get to the point that they no longer keep moisture in the bath then it is time to replace the liner. I usually have a decorative cotton curtain on the outside and the liner on the inside though, and rarely have to replace more than the liner.
One of my son's had a hive incident a couple of years ago. The notice at the allergists office said that pillows should be replaced every 6 MONTHS to reduce allergens in the home. I SO need to work on that.