@Inna22
Yes, I know that guests don't see a breakdown of that and I can see why people would assume if the space is advertised for X number of guests, they can have extra people over without changing the reservation.
It makes sense for you to list at a fixed cost for a whole unit if that works best for you. I would still be concerned though about having random people coming in and out. As you mentioned, there are other issues to think about than just the nighty rate.
Unlike you though I find it does make a big difference whether there is one person or two staying in one of my rooms. It's not just about the utilities, which are a concern as prices soar, but mostly it's that two people just create more mess than one. Couples also tend to do a lot more cooking. For a complete unit that only gets cleaned at turnover, that might not be a big deal, but as a live in host, I have to ensure that all communal spaces are kept clean and tidy on a daily basis.
The last two couples I hosted completely took over the kitchen (and one also requested the living room as an office space because the two of them didn't want to work in the same room), were very messy and also damaged a few things. They were also more demanding than my single guests. It was so much extra work and there is no way it would have been worth it without the extra person fee.
In fact, even with the fee, it wasn't worth it so I decided to only take solo travellers going forward and changed the capacity to one person per room. Now that extra person charge is just for when guests have a friend or family member visiting for a few days. It's not really about the costs/compensating me for extra cleaning and laundry (the extra person fee is quite low), but to stop people thinking they can have overnight guests whenever they want or just move someone in during the stay.
At the end of the day, we all do whatever works best for us, but the important thing is to be CLEAR about it so there are no wrong assumptions made.
This is how I have worded it:
"As I host long-term stays, this room is for one person only. If you would like friends/family/a partner to visit for part of the stay this is possible for an additional fee, but please contact me in advance. Only guests named and paid for will be permitted on the premises as otherwise the Airbnb insurance is voided. Please respect that this is my private home and do not bring visitors, including friends and family, without asking permission IN ADVANCE. Visitors may not stay over night."
It seems to work...