I have the 5.5g 30GB. I'm having a tough decision whether or not I should upgrade to an SD card reader - yes I get more storage and battery life, but the feedback of a spinning hard drive inside has a charm to it
Imo, use it until it breaks. The listening to the spinning disc argument got eaten by a faster ssd on another classic that I have, plus having my whole library in it, so I rarely sync new music. I tended to do so too often in the past and I screwed a Ssd by corrupting it somehow. The lesson, better leave things untouched as they work!
In this case, I meant the original 120gb hard drive. That's the reason why I synced it and left it running with the apple OS. I had to upgrade the battery (bought some cheap ones via aliexpress) and now it works like a charm. The only issue was the first charge, it took the ipod a while to recognise the battery, so having a fire wire cable to feed it the first time should do the trick. Since then, this little grandpa is still rolling for more years, I hope!