My way of sorting calls:
I have an ingenious system for sorting out if my landline calls are for me or not - if the landline rings, it's telespam.
I never list my landline as my telephone number, unless somewhere specifically asks for it, even then I'll leave it blank, as it's rarely required for a real purpose. I think the only time it had to be listed was as a backup emergency number for the hospital or something along those lines.
Or if I'm signing up for something where I just know any call I receive will be some poor sod toiling away in a call centre, THEN I use the landline. My 1571 is always choc full.
"Hi there Mr Tunnah, this is.." DELETE
lather, rinse, repeat every few days.