every 9 years or so.
I have used iPods with the dock-connector, the original iPhone and every iPhone and iPad up to the iPhone 5s now. I collected a pile of chargers and cables and they all are used, still. I'm sure that the charger of my very first iPhone is used everyday. There is no better investment into cables and chargers I have made within the last decade. Similar, but not as good, with the Powerbooks. Most of the chargers have had a very long life, and my very first Magsafe-Charger is still in use, daily. I have no use for the original Powerbook Charger anymore, though.
I own an assorted set of non-Appe tablets (currently Thinkpad T2, Nexus 7) and from daily use (they are fine devices for some uses) I'm very confident to have gathered enough datapoints to say:
"mini/micro-USB2/3 for a mobile phone or tablet on the device-side sucks. It's stupid and clumsy and everybody arguing that Apple should go USB (on the phone) is stupid, too, and most likely does not own such a device but just want's cover up a pychological deficite. Micro-USB-3 is just a really pathetic joke."
Don't force my to use the shit that you consider sufficient and I promise to keep quiet and use my chargers for years over years.
And now please have a look at
Apple vs. Samsung: A Decade Of Proprietary Connectors