What do you do to fix it? Just unplug it or reset it? What indication do you have that your cable modem is “freezing”?

If it happens every 1-3 days, I would suspect that the DHCP lease from your cable modem provider is expiring and (for some reason) not renewing, which is most likely a problem on their end. Let them know that this is happening and ask if they have any ideas. Did this start happening as soon as you got the router, or did it start occurring recently in lieu of any changes on your part? If the latter, that’s all the more reason why it’s probably not your fault.