You do not need to reset the hub as long as:
1) You have not moved to a new home.
2) The Wi-Fi network name (SSID) is the exact same.
3) The Wi-Fi password is the exact same. the exact same.
All you would do is plug the hub into the new router via Ethernet cord.
If you get a new router and the Wi-Fi network name and password are different from before, you will need to remove all of the hubs from your account, reset them and then re-add them to your account.
Your bulbs will stay paired to the hubs as long as you have not reset the bulbs or deleted them from your hub.
This article explains how to reset a hub and add it to a router.