Well the title says it all. I have a friend hows changing tubes every year no matter what. I dont Know if this is ok or not but for me this seems maybe egzaturated given that he plays only 1-2 hours 3-4 times a week....I dont Know... I currnetly have my Peavy Classic wich has 4 x JJEL84 power tubes and 3 x 12AX7 preamp tubes. I migh missmatched the power and pre names. Anyways, how to Know when you need to change your tubes and WICH ONES to be more specific? DO they worn out all the same or power tubes get waisted sooner? What are consequnces of not replacing the tubes at the right time? Thank you.