Replaced my power steering fluid today. The old fluid, at least 19 year old and good chance it was original, wasn't that bad looking. Dark red, no sediment in it.
I used the easy, not as thorough method that mixed the new fluid with the old. I thought it best not to undo the hard return lines. And it if it's good enough for the detail-oriented MrSubaru on youtube, good enough for me. I used a syringe to remove old fluid from the reservoir, put in new ATF, drove the car a bit, turning the steering lock to lock several times, then repeated two more times. Done.