Surely if it was a genuine work call, but the contact name doesn't come up or you don't recognise the number, you could just let them leave a message? And then you can call them back? If no message is left, google the number. Usually if it is a spam call the number will come up on one of the many sites which monitor spam calls, then you can just put it in your contacts as spam so you will know the next time? I rarely use my landline but I have it for broadband. I never answer it. It is on permanent voicemail, but I have the speaker on so if it is someone I know I can then just answer it. If it isn't, and it's spam, they usually hang up as soon as the recorded message starts. I am supposed to be registered on the TPS scheme for both the landline and mobile. I rarely get spam mobile calls any more, but I do still get a few on the landline.