I have two sisters, 8, adopted at 4 months the from Cats Protection.
They are very affectionate with me but could take or leave each other. They sleep on the bed beside me (on their own electric blanket!) and rarely go outside unless I do.
Cat 1 is lazy and super cuddly. She would be on my lap all day, every day if she could. She follows me everywhere, even sitting beside the bath. She's also opinionated and loud!
Cat 2 is more anxious about other people but still appears to adore me. She's hesitant about coming on my lap but will always sit beside me and taps my arm when she's like attention. She's still very playful and regularly gets the zoomies, hurtling in and out of her tunnels and trying hard to engage her sister in play, to no success!
I'm very tempted to get a male kitten. I think Cat 2 might appreciate a playmate (she had a friend before I moved house) and it might make her slightly less anxious generally. I'm also aware the girls are the same age and only going to get crotchetier with age so now is the moment.
However, the last thing I want to do is upset my girls.
How do you know? I'm disabled and home almost all the time. My cats are my world and I certainly have love for more.