This is a critical strength of the RTL8188CU. Drivers are available for:

While the Pi Zero W has built-in Wi-Fi, the original Pi Zero (non-W) and Pi 2 lack it. The RTL8188CU draws very little power (under 500mA), meaning it won't brown out the Pi's USB port.

Realtek RTL8188CU Wireless LAN 802.11n USB 2.0 Network Adapter

Mean Time Between Failures (MTBF) for quality units: ~50,000 hours (consumer use). Cheap clones may fail within months due to poor soldering or inadequate power regulation.