They don't sell small parts for the new ones (although a replacement mechanism for $90 beats the competition), and the G-spring units needed it frequently because the springs had bad wear characteristics. I rebuilt my 1996 G-spring levers every few years until I broke a discontinued spring and moved on to 10 speed Ultrashift in 2012. If you do your own work that's not a big deal (the hardest part is taping the bars) although many people don't.