Stand by time is the time a fully charged headset will stay on without having been used for even a minute.
Talk time is the longest time you can have a conversation till the battery dies
Charging time is the time your headset will take to fully charge.
Talk times and standby times can vary widely. Depending on your usage, look for headsets with a minimum of 4 to 5 hours of talk time and standby time that ranges from less than a week or two weeks. Talk time is a better measure for judging than stand by time. Some brands also have listening time where less battery power is used due to non usage of the mic. And obviously, any headset that'll take less time to charge quickly is a winner, 'cause who wants to wait to use the wireless bundle of joy.
Pick a headset that has a standard micro USB charging port to allow charging anywhere with your phone charger.
If you've picked a headset with multi point selection, prioritize your usage. Planning your battery usage is key. If you usually have long conversations, you don't want your battery dying on halfway.
Some Wireless Headphones have to be charged and and some use AA/AAA batteries, which is a more convenient option. Chargeable batteries have operation time of upto 20 hrs. Since wireless headphones are mainly used fro listening purposes, they can stay on for longer.