We have had the same landline number since moving to Oregon 11 years ago. We have talked about getting rid of it, but with all the kids scattered who knows where half the time. Having the landline gives me peace in case the dreaded "midnight call" comes through.
Our older grandkids know this number is always going to remain the same. So if something happens to them they can call. Hopefully they won't be as stubborn as their goofy parents and not call until the crap hits the fan.