I won’t do it so friends can sit together, but I consider it if it is a young child. Not a teenager or sub-teen, but a child. Also, if it is an elderly person who needs assistance.
A teenager or sub-teen should be independent enough to sit on their own.
And I am not going to do it so a couple of friends can “hang out” together. Or a husband and wife. I think it is rude to even ask, unless it is a young child or an elderly person who needs assistance.
Some people are considerate and some aren’t.
I wish a woman traveling with a toddler HAD asked me to change seats so that she could sit next to her child on an 11-hour flight. Mom was on the aisle, the child was by the window, and I was stuck in the middle between them. Guess who had to wait constantly on the child and help her with her meals, drinks, snacks, movies, toys, etc. and listen to her babbling when she wasn’t watching a movie? She did not take a nap during the entire flight. At least she never cried.