I just got my first pair of AirPods. How long should a charge last?

Phone calls drain the battery faster.

Listening at high volume levels drains the battery faster.

Transparency and noise cancelling drain the battery faster.

Apples official battery estimate:

Battery

AirPods Pro

• Up to 4.5 hours of listening time with a single charge (up to 5 hours with Active Noise Cancellation and Transparency off)4
• Up to 3.5 hours of talk time with a single charge5

1. Testing conducted by Apple in October 2019 using preproduction AirPods Pro with Wireless Charging Case and software paired with iPhone 11 Pro Max units and prerelease software. The playlist consisted of 358 unique audio tracks purchased from the iTunes Store (256-Kbps AAC encoding). Volume was set to 50% and Active Noise Cancellation was enabled. With Active Noise Cancellation and Transparency turned off, listening time was up to 5 hours. Testing consisted of full AirPods Pro battery discharge while playing audio until the first AirPod Pro stopped playback. Battery life depends on device settings, environment, usage, and many other factors.
2. Testing conducted by Apple in October 2019 using preproduction AirPods Pro with Wireless Charging Case and software paired with iPhone 11 Pro Max units and prerelease software. Volume was set to 50% and Active Noise Cancellation was enabled. Testing consisted of full AirPods Pro battery discharge with a cellular phone call until the first AirPod Pro stopped playing call audio. Battery life depends on device settings, environment, usage, and many other factors.