I just worked on my Infinity Alpha 50's over the weekend. Had two tweeters cracked due to somebody pushing on them several years ago. Just got around to looking for replacements which i surprisingly found. That's the only thing i've ever had to do to my system which is almost 20 years old. I have the Alpha 1200s sub, Alpha 37c center channel, Alpha 50 towers, 4 of the Alpha 25es surround speakers with a Harman Kardon AVR520 receiver and PA2000 amp.