[jcommin]

Not a rental guy but

This is a definition I live by in my line of work. All of this is subject to interpretation and I yield to those in Finance.

“ A significant improvement in the performance of equipment, either from an operating cost, efficiency, safety or a quality control standpoint. At the time the asset was acquired, there was an expectation of the performance of the asset, in order to be capitalized, the expenditure must increase the performance beyond the initial expectations.”

In my world:

asbestos removal - capital
trash removal - expense
new bathroom - capital I would capitalize trailer rental too.
carpet is capital
painting is expense

I would seek the advise of an accountant.