Our guests have the complete use of our remote cabin on a mountainside, 30 minutes from the nearest town/supermarket. I do not advertise that breakfast is provided - but I do. I always think of the guest who may never have experienced such a remote setting, or do they really believe that it is half an hour from the nearest anything. And some guests drive straight from work on a Friday and arrive late, and may have 'forgotten' to bring groceries - I do not want anyone to wake up their first morning with no food or even milk for their coffee!
So a few days before arrival, I message the guest to give detailed directions and to let them know that bread, milk, juice, fruit, butter, tea/coffee, eggs and bacon will be in the fridge for them so not to worry about bringing those items.
By not promising it in the listing - it is an 'extra' - which means I can keep it flexible (for example I am rethinking the bacon option - it is expensive and I do not agree with the health aspects of it so it may be off my list very soon) and the guest is normally pleasantly surprised. I also always include a bag of chips and salsa, some chocolates, and sometimes a bottle of bubbly and a pancake mix and fresh blueberries, especially if they guests are celebrating an anniversary or special occasion (over 60% of our bookings are for that special something).
Getting my expenses together for the tax year evidences that this is an expensive thing to include in my already discounted listing price..... but it would be hard for me to not do - as I think a guest who only has 2 days to take their relaxing break in the mountains shouldn't have to miss out on their first breakfast because they forgot to include some basics during the rush to get here.
Best Wishes.