Tube arch

Ok I’ll keep this short. So my last post was about a tube arc. Took out a resistor on one of my Audio Research Ref 750s. I replaced the resistor and put in a matching KT150. My question is how can I avoid this from happening again. Someone said that when the tubes get up there in hours there is a very good chance of an arc will happen again. After a certain amount of hours should I just change all the 18 KT150s ? Even if they still sound good ? Btw. I have always had SS amps and pre amps. I finally bought an Audio Research REF 6 pre a few years ago and had it upgraded to the 6SE. But as far as tubes amps the Audio Research REF 750s are my first tube amps. This will always be on my mind now especially when the hours of the tubes start reaching a high hour number. Thank you. Mike. Ps I heard that this was a pretty rare thing to have happened and it was probably caused by shipping.