if you want a decent and lower budget one i'll definitely recommend yoobao. if you got the money and wanna go for good ones i recommend eneloop. I got friends using both and no complain so far.
usually what i'll do is just leave my powerbank on charge overnight. not sure whether it will spoil or not but i'll try to do a full discharge and full charge at least once per week

I bought a Yaobao 13000 maH Decepticons heh heh heh. Make sure it's Original, if it sounds too cheap, most likely it's fake. Yaobao has a website where you can scratch the box and you can input the code to check if the product is fake or not.

I have had no issues with it. It is able to fully charge my Lumia 920 (2000maH), iPhone 4s, iPad 2 (2 units) and an iPhone 4 .... and still have some charge to do another round for the iPhone 4s .... it is that good.

It's a China brand and some people may have issues with that but remember in the early 70's, people say the same thing about Japanese made products as well.

Th fake ones ar going for RM160 in some of the Low Yat stores but I insisted on an original one so the guy went somewhere and brought me a box which is a bit different that the fake ones (with the name of the sole distributor clearly marked on the box). I paid RM260 for it.

Not sure about iPhone 5 because I don't own one. I decided to go with Nokia Lumia 920 after the 4s.

The original one comes with a 3 pin plug to charge the PB and some accesories (Micro USB, Micro USB to 30 pin etc etc) but I am not sure abiut BT headsets etc (if it has a MicroUSB charging port it shout work). It comes with 2 charging port (1A and 1.5A I think, so for the iPad or iPhone, you need to use the higher ampere slot)