Cracking tips.
Put a note by the landline of elderly parents reading 'No Thank You', encouraging them to consider every call from someone they do not know to be a scam call by default and to say it - and then to put the phone straight down. If it is real and important, someone will send a letter. Older people consider it to be impolite and may be lonely, but they really need to put the phone straight down and not begin a conversation with the caller - conning people is a scammer's vocation and they are very good at it.
Only answer the door to family, friends, neighbours, people you are expecting, the postie and delivery folks. Just ignore anyone else. Don't even answer the door. If an elderly relative cannot see a caller from inside, install a mirror or a very basic door cam - not something complicated requiring a subscription and apps.
Any automated phone call from a bank is fake. They have to securely ID you before speaking to you about your account.
You will never get a genuine call from any global corporation, or from the Prime Minister/President, or Madonna. So if they say they are from Microsoft or Google or whomever, just put the phone down.
Never click on any advert on the internet. No problem reading them, but if you are interested in a product, check it out on Amazon or ebay. That doesn't invalidate online advertising, it just makes it safe.
Never click on a link in an e-mail. Go to the site. My bank sends me e-mails. It really shouldn't. E-mails are not secure.