I'm qualified to do it, but have had remarkably few amp problems requiring service. And I wouldn't know where to begin with the modern stuff unless it's something easy like a broken switch. I've fixed basses, and recently re-glued a seam on my cello. I've also fixed home appliances. I've repaired cables. I think that the lighter, smaller gear tends to get less abuse because it doesn't get knocked around as much. For instance my amp head goes into a small backpack when I'm done with a gig, and doesn't come out until the next gig. I load and transport all of my gear myself. So it lives a pretty cushy life.