This is a non-trivial issue, since the cost of repair may be the difference between misdemeanor and felony.

Per CaseMaker Digest:

A non-expert property owner's testimony about the cost of repairing or restoring his damaged property could be sufficient without further evidence to prove the pecuniary-loss element of a criminal mischief offense

Short name:     Holz v. The State
Court:    Texas Court of Criminal Appeals
Date decided:    September 22, 2010
Docket number:    PD-1786-09
Judge:    Paul Womack

A complaint was filed against the appellant, alleging that he did intentionally and knowingly damage or destroy the victim's tangible property. Later, the trial court convicted the appellant for the lesser-included offense of Class A misdemeanor criminal mischief. The appellate court rendered a judgment of acquittal, concluding that the victim was the state's sole source of evidence regarding the amount of pecuniary loss and he had provided insufficient evidence to support the appellant's convictions. On petition, the Texas Court of Criminal Appeals held that a non-expert property owner's testimony about the cost of repairing or restoring his damaged property could be sufficient without further evidence to prove the pecuniary-loss element of a criminal mischief offense. When the owner of the property was testifying as to the value of the property, he could testify as to his or her opinion or estimate the value of the property in general and commonly understood terms. In the instant case, the testimony of the victim was an offer of the witness's best knowledge of the value of his property and such testimony could constitute sufficient evidence for the trier of fact to make a determination as to value based on the witness's credibility. Thus, the victim's opinion regarding the value of the property was sufficient to show the amount of pecuniary loss. Therefore, the appellate court erred when it entered a judgment for acquittal. Accordingly, the judgment was reversed.