Mcintosh C 220 pre amp tube life....

Hi Folks:
Recently purchased a McIntosh C 220 pre amp (Store demo) with about 200 hours on it. Any idea on how long the tube life is for a 12AX7 A set of tubes in a Mcintosh? I also bought the MC 252 amp to go with it. Wonderful combination. Just wondering if one listens on average of 2 to 4 hours a day, how long I should go before changing the tubes out. Thanks!
Give Chuch Hinton a call at McIntosh, or get on their site and email your question to him. A very helpful guy.
You should be able to get 10,000 hours out of a set of healthy tubes. If you want to be conservative you could change them at 6,000-8,000 hours. Just keep a spare pair on hand in case one dies early.
One more thing, when I had my C2300, I was told 10,000 hours on the tube life. I miss my C2300 and am thinking about getting another one.
It's usually 10K hrs. however, sonically they might go down hill sooner than that. Since it happens so slowly, the only way to know for sure is to replace them and see if you hear an improvement in the sound.
Replace the stock Mc tubes for improved sonics. Genalex Gold Lions or Psvane Treasures.
I have owned the C220, C2200 and now the C2300. I have never needed to replace my 12AX7's. I use my preamp most of the day for my fm. I think the tube life also depends on how many on/off start up cycles they endure.

Very satisfied with the tube life and reliability.