Deducting expenses after depreciation has "run out" on rental property

We live in a large home, and 1/2 of the house was converted to apartments (2 of them) years before we owned the property.  We live in one part of the home and rent out the apartments.  We have depreciated the apartments over the years, and if I recall correctly, the depreciation was good for 27 years.  We are on year 24.  No plans on moving, however, during the past we refinanced the building (home) part way when loan interest went way down.  I am trying to determine what I can and cannot deduct once we have passed the 27 years of depreciation, even though our mortgage will still need to be met.  For example, if we paint the house, do I only get to depreciate the cost of the apartment portion for the years left on the depreciation schedule, or is there some way to continue to spread out the cost over time as far as taxes are concerned?  If I wait and paint the house after I have depreciated out the apartments, can I deduct the full amount for the portion of the apartments?   Normally, large things like that have to be depreciated over time, so I don't know how this would be handled.  Any advice or insight will be helpful; thank you in advance.