Refrigerator damage - deposit

[Brad Rondeau]

My tenant in my Laguna Niguel condo is moving out after 8 years.   They have been good tenants and will probably get most or all of their deposit back.  Originally I was going to take the new Samsung refrigerator with me ($1,100+) and let them get their own.  I later asked if the wanted to rent the fridge from me for an additional $20 per month.  They  (reluctantly) agreed.  A few years later they said the ice maker stopped working and wanted it fixed.  I told them to just get Ice trays because I did not want the hassle/expense of the repair.  They said they would buy their own fridge, stop paying the fridge rental and store my fridge in the attic.  I said ok.  As they are getting ready to move out I see my once beautiful stainless steel Samsung in the Garage with a huge dent in the door.  There is also some corrosion on the metal in different spots.  

Before seeing this I was planning on putting the Samsung back with ice trays and be good to go.  After seeing it, I can't really use it now.  Does the tenant bare any responsibility here, or is this all on me?