apple id password

I may not have been clear, but each time that notifications shows up I do that and re-enter my password and then a few days or more later the notification shows up again and I re-enter it again. It has happened a number of times.

So why does it keep happening and is there a way to stop it .... in many years never happened before now

OK ... not good news.

After going to Apple Chat and when the advice to shut down the phone and then restart did not work, went back and was transferred to a Senior person who then had someone call me back from Apple support. She said she had heard of this, but was not currently listed as a problem so evidently cannot an upgrade to solve it. She said it could be an email problem .... since the apple id included your email address, but when pointed out all my other devices do not have the problem it was not the situation in my case. To find out if it is a software problem, need to set the iPhone back to factory setting and then not do a restore for a while to see if the problem is still there ... if it is not there, then a software problem and cannot restore from iCloud since just re-introducing the problem but need to reload everything all over again .... if this was the case even getting an 8 or X would not solve the problem. If still happens then it is not a software problem. The main problem with not signing back in is cannot download new apps or do an iCloud backup without re-entering the password otherwise all else should work.

So no real answer. Will think if I want to do all that or not... if someone else tries, can you let me know

When updated apps and downloaded a few from App store to try some others, but deleted them.

I am not sure, but may have started after upgrading to iOS 11.2 ... could that be the problem