What is meant by betterment?

Answer 1

Betterment is a term that is used in the discussion of money damages to which a person is entitled in a civil claim. It refers to the fact that the function of damages is to make the claimant whole, and not to place him/her in a better position than he/she would have been prior to the incident that gave rise to the claim.

An example might be an auto collision/ If the innocent party had an older car, but had damaged parts of it replaced with new, when used parts were available. If the innocent party later sued the at-fault party to recover the cost of repair, the at-fault party might argue that he/she is liable only for the reasonable cost of used parts, and that anything more than that is "betterment".