Regarding leaving the Pacific on 24/7 it was my tendency to always do so. The DAC is quite gentle on the output tubes and I would rather them be run gently than have the wear and tear of being turned on and off.Any reason to leave the Pacific on 24/7? I shut down mine at night and turn it on the next day, which is what Lukasz recommends. I haven’t tried the Sophia’s on my Pacific, which currently has a much pricier WE 274B.
The small active triode tubes will fade faster, but they are inexpensive to replace anyway.
If you're looking for a reason NOT to, I suppose I should mention the rectifier tube will be run pretty much "full blast" and will die quicker. If you have an expensive or rare rectifier tube, this may be a concern for you.
In my personal life, I'm extremely busy and have limited time to listen and often find myself only able to steal an twenty minutes here, forty there, often unplanned--I tend to like having things warmed up and optimal for this times I can sneak some listening in and find value in this approach.