Most times when Apple hardware breaks, it's generally a trip to the Genius Bar or an authorized Apple Repair location. However, Apple severely restricts what can be repaired onsite due to intentionally restricting spare parts. Additionally, the experience typically costs the same as when purchased new to fix. Rossmann Repair Group in Manhattan, NY bypasses all of this, providing excellent service, expert troubleshooting diagnostic and capable of repairing anything on-board. They also resell all of their high-end soldering equipment and supplies at store.rossmanngroup.com.
Network 169 offers several routing troubleshooting challenges and configure 'how-to's' using GNS3 or VIRL platforms. Also offering great blog discussions around each platform differences.
Network connectivity issues or general network slowness due to congestion can be hard to pinpoint root cause. The open-source utility Wireshark is the go to for looking under the hood of network traffic. Install Wireshark on a laptop, create a mirrored port (SPAN, RSPAN on Cisco) on the core switch. A mirrored port will see all traffic across all VLANs and allow Wireshark to promiscuously capture packets/frames and report them in a straight forward way. Communication thread(s) streams can be reviewed in isolation and multicast or flooding can easily be seen and source or destination identified for resolution.
My Personal PC
One of many ways I practice DR for myself and customers is not activating my Windows OS. Every 30 day I will wipe out my C-drive and reinstall Windows 8 (previously Windows Vista & 7). Sometimes if I'm feeling lazy, I will 'rearm' the license on the last day to give me 14 more days before activation is required. You can 'rearm' the Windows license only 2 times, the command is (run Cmd Prompt as Administrator): slmgr -rearm