How long is the break-in time for a Sophia Electric Blue 6SN7 tube?

The blue SN7s are good tubes.  I bought C grade tubes, which are fine for my application.  At $99/tube, these are still pricey tubes.  I had one go bad at about 6 months.   It went microphonic an had 60 Hz hum issues.  I would not leave these tubes on 24/7.  Most of the ModWright stuff I have owned does not require a very long warm up time compared to other pieces in my system.  When possible, I turn everything on about an hour before I plan to listen and that seems to do the trick. 

My experience with Sophia tubes in general is 150 hours is the optimal point but I will admit, I have never had an amp with the 6SN7s in it.  I would trust Sue.  

Can't see any reason to leave an amp on 24/7 unless you have very restricted listening windows and you need to make every minute count.  Otherwise, you are just burning away money.  I can't speak about Modwright but my amps take 20 minutes to warm up.  

You'll notice change and settling between 100-150hrs.  No need to leave them on 24/7, and 20-30min warmup seems to be fine.  I run the former TJ Full Music 6SN7 previously noted as being one of the OEM for Sophia 6SN7s but may have changed over the past few years . They are nicer tubes than some of the other re-issues and vintage N7s I've tried, still running them now. Hope they last longer than a year or more.  

Thanks everyone for your information--much appreciated.  I may just start turning things off between sessions.  I've had the 3 tubes in my DUDE on other than during storms 24/7 for about 4-5 years with no drop off in performance so far.  The MW 5400 had been unchanged in the same way since about 4 years ago.  Still has the same NOS Mullard GZ34 tube in the PS.  

Bob

Thanks all for the helpful information.  I must eat crow on a couple things I wrote:  1.) There was an incredible difference in sound quality when I finally replaced all 5 tubes in my TRL DUDE was NOS RCA tubes from Andy's Vintage Tubes in Michigan.  The sound was so much better than when I first got the DUDE from a previous owner that I'm not sure he even knew what the DUDE could really sound like.  

2.) I am now turning off the system between listening sessions to conserve the tube life as best I can.  It doesn't seem to take that long before the system sounds near its best--then subtlety gets better from there.  

Bob