I've been running the same eheim 2211 for around 10 years. Taken apart once a month and no leaks. If you take care of your stuff it works.If you maintain them like #K78MG explains and required if you intend for them to be effective in saltwater (taking them apart every week to clean and reassemble) over time the risk they will leak is high. In a freshwater system, maintenance is much less frequent.