Hi Ben
It is another good topic!
I think that having a holiday apartment or house to let is kind running a small business.
Every business must have insurance and some fund for maintenance and also self insurance.
It is not practical to get into lots of details to reach some figures. It can be useless and may depend on statistics and probabilities.
I see some costs are regular expenses, such as soap, electric energy, fees and whatsoever is in the same category.
To form the price we must include such items, of course considering our own reality and particularities.
If we do that, It will give as certainty that, in the short run we are doing well.
I think that the approach for depreciation and maintenance can be different.
I usually consider that I have to save separately about 4% of the lucre to be a kind of self insurance fund for maintanence and to replace things such as equippaments, pieces of furniture, linens and towels, (worn out things or things that broke due to some incident). It can be used even to repair other damages to the property or to paint the walls when it is necessary.
I have heard that, hotels save apart about 4% of the lucre for the same reason that I have described before.
By doing that we can be sure, that we are not wasting money along time or in the long run.
We can also be sure that, we will have money for maintenance and to invest or spend money (once in while) on something to make the property better and up to date.