It’s great to have a portable charger with a big battery that can recharge your phone multiple times before needing to juiced up again itself. Batteries are quite heavy though, and sometimes you just don’t have the space to lug around a big portable charger.
You’ll have to recharge most portable batteries more frequently if you use them at home (as well as when you’re on the go), and your wall charger won’t do much of anything if you’re away from an outlet.
Samsung ran a series of ads calling iPhone users “wall huggers,” and they were pretty annoying… mostly because they’re true. Apple’s iPhones do plenty of things very well, but it would be hard to find anyone who considers his or her iPhone a class-leader when it comes to battery life.
Finding the right portable USB battery pack for you will always depend on your particular lifestyle. You don’t want something strong if you’re not a power user. You don’t need something compact if you always have a bag on you.