You should restart your modem periodically. Once a month is recommended.
Restarting your modem periodically often solves many connection and performance problems, such as:
Restarting, or rebooting, your modem will restart the modem’s operating system and will thus correct any errors that might have accumulated. It also allows the modem hardware to re-initialize its profile of your line, which may better suit current conditions if your line is variable. Bell Canada, the provider of the line, recommends restarts once a month.
The easiest way to restart the modem is to power cycle it (hard restart):
If you have a separate router connected to your modem, turn it off after the modem and then wait until after the modem is on again to turn the router back on. This ensures the router will be coordinated with the modem.
Most modems can also be restarted from the modem interface (soft restart).