Q: Do I have to worry about the U.S. DST change on my routers and switches?

A:

No, not likely. Even if your device is an NTP server for the rest of your network, the timezone really does not matter. The device's timezone settings does influence the timestamps on the router logs and the syslog messages it sends. It could also come into play if you are using time-based ACLs on your router (does anyone actually do this?). However, if you really want the local time on the router to be correct, you do not have to upgrade the IOS to a version that incorporates the new United States DST start and end dates. Just by adding one line to the config on your router or switch, you can change the DST policy. I'll show both timezone lines for my devices; you will want to change the timezone name in both lines (which is used for display purposes only) as well as the offset from UTC unless, like me, you are in the Eastern time zone.

clock timezone EST -5
clock summer-time EDT recurring 2 sun mar 02:00 1 sun nov 02:00