Upgrading VS Maintaining Your Home

This can be extremely complex to understand for some. I have come across this situation on several occasions, sellers not understanding an upgrade to the home versus maintaining the home.  They tend to think that maintaining the home counts as an upgrade. 

Maintaining:
For instance, if your roof is leaking and you pay to have a new roof put on, you are maintaining your home. Had you not put a new roof on the home you would have significant costs associated with rain and weather damaging your home. 
If your windows have lost their seal or have moisture in between the pains and decide to replace them, you are maintaining your home.
If the a/c or heater goes out and you get a new high efficient unit you are again maintaining your home. Without the repair you would not have heat or a/c. 
If you have plaster walls instead of sheet rock and you change to sheet rock you are maintaining your home.  You are bringing your home to the standards of a majority of other homes on the market to what people are expecting
Same if you have stains on your carpet and decide to replace it, you are maintaining you home.
Painting walls would be maintaining- keeping the home fresh and new. 

By maintaining your home you are keeping up normal repairs associated with living in the property. (also considered normal wear and tear)

Upgrading:
If you have a functioning bathroom sink and vanity with no repairs needed and you decide you want to put in a new vanity with a vessel glass sink, you are upgrading your bathroom sink/vanity. You are making the bathroom more desirable and likely appeal to more buyers since your bathroom is trending with the newer homes updates. 
If you have decent kitchen counter tops and decide you would like to replace with granite counter tops you are upgrading your kitchen.  You are creating a value add to the home by making it more sell able or desirable. 
If you change outdated features of the home to more modern or "with the times" updates you are upgrading the home. (this would not be damaged or broken items/repairs, only fully functioning items that are replaced to keep with the times)

You cannot expect to be reimbursed above and beyond for maintaining your home, where as upgrading may warrant additional money (not a $1 for $1 return). It is expected that home owners are to keep their house in average to good condition to hold their value.  By not maintaining your home you will eventually have significant repairs, nothing lasts forever without upkeep.