All of your current Micro USB cables will work fine. However, they won't utilize the fast charging feature. That only works with chargers that have built in fast charging capabilities.I'll start....
Do I need to get all new chargers like the car charger that I have been using for my GS4?
Will some apps behave differently due to a different OS version?
All of your current Micro USB cables will work fine. However, they won't utilize the fast charging feature. That only works with chargers that have built in fast charging capabilities.
As for the apps question, it's definitely possible that some might behave differently with the s6 (Lollipop TW). But as long as the app is still being updated, the developers are usually pretty quick to push an update to fix any bugs that come up with a new phone.
Is there a car charger that does rapid charging?
I am thinking of buying a wireless charging pad or a rapid charger for the office. The charger out of the box is a rapid charger?