This paper deals with some Romanian hydroelectric, low and high head, power plants having either long lasting commercial service or with early failure periods, which were built some years ago. All are facing problems due to strong wear and/or design and manufacturing defects. The troubles required promptness in rehabilitation, refurbishment and modernization. Snapshot-oriented programmes exist both for those with long lasting commercial defects, thus leading to self-revealing faults in operations. Detailed cases are documented.