I got rid of my dining table because it was just a crap dump and never got used for meals. We eat on the sofa all the time, I'm totally not bothered at all. They know how to behave when we eat out so that's all that matters.
I am a stickler for language, as dd is autistic and echolaic, so I avoid bad language in front of her so she doesn't copy me, but I swear all the time otherwise. DS is 19 and I still 'OI!' at him if I hear him swearing, but I know he swears when he's with his mates, doesn't bother me. I see it as being respectful and knowing when and where swearing is acceptable. My friend's son was allowed to swear all the time and doesn't know when to stop now, I just find it annoying, especially when every other word is profanity and not just in context.
Bumbum willy head smelly poo doesn't bother me, it's a bit of silly fun 
I don't allow damage to furniture, walls etc, simply because it really depresses me to see my home looking scruffy and I can't afford to repair and redecorate all the time. I stay out of the kids' bedrooms on the whole, ds is 19 so can deal with his own space without me invading his privacy, and dd likes her things to be 'just so' so I don't like to go in there messing up what she spends a lot of time organising in her own way.
Please and thankyou are mandatory, it's the most basic manners and takes no effort so I don't think there is any excuse tbh, unless your child is so disabled they simply can't do it.
I was never too bothered about allowing DS to watch 15 movies and restricted games once he got to about 12, and 18s from about 14-15, although most of the films he likes aren't too offensive anyway, mostly comedy with rather puerile themes 