This topic has intrigued me so I've been following this thread after my original post and looking some stuff up on my own, and really early twenty-somethings living at home is actually really common.
This thread has sort of went from parents who enforce strict rules on their adult offpsring to what it means to "be an adult" and the cost of living. Disregarding the former because lol, the cost of living is probably the biggest outside factor in someone's choice, or lack of, when living with their parents. The mid-20s is actually the most average age people begin to establish their independence, which means no borrowing money from mommy/daddy or any relatives, and being 100% independent, disregarding bank loans. So, 18-23 year olds living at home is really not that much of a spectacle,
considering that 51% of young adults in that age group are still living at home. The topic of the thread, however, is about strict rules and expectations when living with your parents.
That being said, I think that Livewire hit the nail on the head with most of this as far as the actual topic at hand about rules enforced by parents on their adult offspring. As with any situation where you share living space with someone, be it roommates or family, there are going to be some expectations, and it is all dependent on the individual situation. It's not uncommon for roommates to distribute chores among themselves, not unlike a parent asking you to clean your own dishes, vacuum/mop the house, etc., etc. I only mention roommates because they are incredibly common in young adults who have just moved out and are looking to ease the stress of financial responsibility.
OP also mentioned checking in with your parents. I don't even see this as a rule, unless they enforce it, so much as common courtesy. I would like for the people I'm living with to know if I'm going to go grocery shopping or if I have a doctor appointment. The same would apply to a spouse or significant other you were living with, I would imagine. I don't think it's strange in any situation to let people know if you're heading out somewhere or to let them know if you're going to be coming home late.
It's all a matter of background and how one was raised when it comes to this, because there is a very big range of opinions when it comes to these situations. Some people have different ideas of what is and is not strict, some people have different opinions on young adults living at home. It's all a very subjective matter based on individual experiences so it's not something you can really have a solid debate on. What may be strict parenting to you may not be strict to someone else. I think it's pretty universally agreed on that you should pay what you need to pay and clean up after yourself, and hopefully hold a mutual respect with any people you are living with, parents or not.