Those curtains aren't beige naturally. They started out snow white, but 17 years of 2 people smoking 3 packs a day with all the doors and windows tightly shut will do that.
I'm renovating a house that was previously occupied by smokers. I knew going in that the "beige" paint was not a color that anyone had originally selected for the interior, but I was very surprised one morning to find that the new coat of paint I had applied the day before (and which seemed fine at the time) had flowed down off the tops of the walls overnight, creating long rivulets of paint running down to the floorboards. I had to remove the nicotine layer with mineral spirits to get the paint to stick. Somehow, there's no cigarette smell in the house, which is a happy miracle.
Had the same thing happened to me.
Bought a house that the previous owners were chain smokers.
Spent all day getting the kitchen painted a nice brick red.
Left to go get supper.
Came back to the same beige walls from before painting.
All of the paint had slipped down and off the walls.
Great mess to clean up and start all over.
For bonus points, the previous tenant in my house was apparently also running a 3D printer business of some sort, so there's a fine black powder in all sorts of unimaginably impossible-to-reach places. And he did his own electrical work, making it a miracle that the house never caught fire.
IF they also had a hobby of reloading bullets, that fine black powder might be easy to clean up with just one match..... of course, it will just make a bigger mess to clean up.
Curtains are stupid expensive, I have a big window with curtains that are in dire need of replacing but I'm looking at several thousand dollars for just that one window.
I guess it depends on how fancy you are. I get most of mine at the thrift store, and for rooms that I want something specific, I just buy them online. My office window is pretty big, and it required 4 panels at $45 each, so that's only $180.