Keeping deposit for repairs: Original or replacement value

[Jeff Ryan]

  I had tenants leave recently.  I had new carpet installed in 5 bedrooms and a hallway before they moved in 3.5 years ago.  (This a larger single family home rental).  I know, I know...now, carpet not a good idea in these houses...

  But, the carpet never vacuumed, cared for in the least, ripped and stained in several places, left utterly useless, and I had to tear it all out.  I am going to replace with LVP now.  When deducting this cost from their deposit, is it the original cost of the carpet (with installation) to deduct, or the replacement cost of LVP, (which I will do the install part myself).  Either one will entirely eat up their deposit, I'm just curious what to use officially.  Sorry if it's obvious/stupid question and/or asked before, but thanks!