Actually, it's "add or maintain value" in a property.
Sometimes it can be difficult to differentiate between a repair and a property improvement. For example, if the fan motor in the outside A/C compressor burns out and you pay to have that fan motor replaced, that's a repair because The expense was incurred to return the compressor to the same usable condition it was in, prior to the event that caused the central A/C to be unusable.
However, if you instead elected to replace the outside compressor unit with a complete new unit, that's a property improvement. There's no doubt that a "new" unit will fetch a higher price for the property, than you might get with a 10 year old unit still there; even if that 10 year old unit had a brand new fan motor in it, the unit is still 10 years old.
