A repipe is the process of replacing old and/or failing waste and water piping. Repiping can be complicated by old connections, framing issues, or little to no crawl space. A qualified journeyman plumber can determine where your piping is within its service life, and whether or not it is a better value to do a repair or a full repipe. A job permit is required for repipes.
Piping fails for many reasons:
Low flow or reduced water pressure
Scalding shower water when the toilet is flushed
Re-occurring debris/rust found in fixture aerators
There are a number of older piping materials that have been used throughout the decades, many of which can require replacement.