Lifespan of Synology NAS

[Mike48]

Hello all,

I am wondering about the expected lifespan of my Synology DS414 and what people's experiences have been this regard.

Specifically, I wonder about--

1. Usual lifespan
2. Warning signs of failure
3. Practicality of repair
4. Ability to move discs to a new Synology
5. Preference for a new one (Plus series, Value series, j series?)
   

It is used for audio and shared file storage.