Bad news - my pump died yesterday. Good thing I have 2 in my loop so should be fine until I'm back to my 2xD5 setup.

Interestingly, I've heard some opinions that DDC are fine when running continuously, while they don't like frequent on/off.
My pump died after running continuously for 4 weeks - at very low temps (water @21C, case @20C with fan directly cooling both pumps and with the housing cut for cooling) - I was doing online backup.

Pump was fine while playing/benchmarking (which included a lot of on/off cycles) for the past half year.

Lessons learned - I should have stayed with D5...

BTW - redundancy is the king!