As a BSEE, it used to be design/experimentation, hopefully leading to good sound, but it was the entire journey that I wanted. I have built literally dozens of original builds of all types, some worked, some well, others no so good. But it was learning. Built the original $99 foreplay and the first SEX amps (twice), then modded them to Afterglows. I have rolling racks of bins of all kinds of parts and over 600 itemized audio tubes. Took apart tape decks to learn, before I bought a Repro. Today, I still do DIY, but it's with a goal of the shortest path to the best sound I can build. What changed? I'll be 65 in less than a month. Still good health, steady hands, wavering eyesight (but tolerable with a good eye loop), but, more listening and less building-to-learn is taking over. I still love to build, like the PP EL34 scratch build still on the bench, but it's after a well respected published design - not much experimentation or pencil and paper design needed, just good parts selection and layout. Same with my current Crack/Speedball, Eros, and Mainline, and looking forward to the BH DAC. Time to enjoy what my labors have wrought ....