The problem is that there is no observed consistency with our product in salt chlorinated pools as every pool is different and not everyone takes care of their pool exactly the same way. Those variables can end up causing catastrophic damage, sometime almost immediately after installation. It is very important that the unit be properly bonded, salt levels maintained and the sacrificial zinc anode be replaced regularly.
When using the Fastlane in a salt chlorinated pool, we do strongly recommend that you would change your motor and submersible hoses every two years. With that being said, it is possible that they may fail before that time. It is also possible that they could last for many years to come.
If you using standard chlorine for your pool you can easily expect to get 5 years out of it before you may need to change it. The underwater motor costs $525 and a new submersible hose kit (if necessary) is $350.
The swap out is not very difficult at all and will take 2-3 hours. It will require removing the Fastlane from the pool, disassembling the upper housing from the lower housing and removing the propellor motor mounts so that you can swap it out.
Conversely, when using any other type of chlorination for the pool, we do not recommend changing the underwater motor out for 5 years.
Please let me know if you have any other questions.