"The Thinkpads that changed the charger connector when we went from T4 series to T6 series and now again with T440's?"
16V/56W thin barrel was good from Thinkpad 360 to T43/R52, 1995-2005. Lots of generations and models in between.
20V/90W thick barrel from T60 to T430, 2006-2014. About six generations.
There were some exceptions, like 135W adapters for hungrier beasts, but as a generalisation, 8-10 years with one connector type isn't bad at all.
Biting the hand that feeds IT
