If you use Cisco switches, it's no secret that their hardware is some of the most expensive on the market. In many cases, this is justified, but it still leaves Cisco users looking for ways to reduce their spend on hardware.
One of the most obvious ways to do this is through the use of third-party optical transceivers. Small-Form Pluggable (SFP) transceivers are designed so that a single Cisco router can accept a multitude of standard plugs, especially ones from the various optical formats on the market. In most cases, they're even plug-and-play without needing a reboot.
When adding new Cisco switches, these can be a serious money-saver.