If you take your photography seriously, you need to avoid one thing in particular: running out of battery power just when you need it. (Have you noticed, batteries never fail at a convenient time?)
The solution is simple. Buy a battery tester, and use it before you go and shoot.
A battery tester, which sells for about $7–10 in your hardware store, is a meter with a “battery” mode. That mode does not just measure voltage; instead, it measures voltage under load.
You recognize it by its mention of batteries (like “AA”, as in this example).
Before every shoot, measure your batteries, and if in any doubt, replace them. That takes away one big drawback of battery-powered equipment.
- Where do you use rechargeables? A: In gear that you use intensively and often: namely, in your flashes.
- Where do you use Alkalines? A: In equipment that uses little current and that lasts many months between battery changes. Namely, in your PocketWizards and similar radio triggers.
One more note: if you use rechargeable batteries, make sure that you use an appropriate meter. NiMH batteries have a lower voltage than Alkaline batteries, so you cannot measure NiMH batteries with a meter intended for Alkalines (or vice versa).