Minor additions can often be prepared straightforwardly as an addendum to the existing appraisal report, without requiring a complete revaluation.
In the case of serious new findings that significantly affect the result, however, a renewed inspection and partial revision of the valuation may become necessary.
What matters here is the temporal proximity to the original valuation date: findings that only emerge significantly later often no longer relate to the condition that was relevant at that time.
Careful documentation of when which information first became known considerably facilitates later classification, particularly in ongoing court proceedings.