Psalm 911 He who dwells in the shelter of the Most High
I rationalized this for years. Granted, mortgage holders require homeowner's insurance, and automobile lien holders also require comprehensive auto insurance. But usually medications, health insurance, long-term care insurance or life insurance are personal choices. And some life insurance can be rationalized off as an investment or tax saving device. But in my life, I had to admit I worried about loss and risks. I believe Psalms 91 is religious hyperbole and is wonderful source material for making beautiful recitations, sermons and songs. But Psalms 91 definitely does not say to do all you can do and then trust God. When I was a Christian, I used the excuse that God expects us to do what we can for ourselves, and then he'll take it from there. But I think an honest appraisal of Psalms 91 shows that its intent is that, if you trust God, he will protect you in all of your ways.
It is interesting, that in the story of Satan tempting Jesus, which I do not believe actually took place, Satan uses Psalms 91 to get him to jump. Jesus allegedly retorts to Satan not to tempt the Lord God. My take on this is that, when the letters of the New Testament were collected, collated, screened and finally assembled into a book, this made a nice story to help people deal with Jesus' death. It was also pretty handy for future believers, because now they can say "Even Jesus' faith was tested, and mine has to be tested also. I will trust in God and whatever happens to me happens." So much for Psalms 91.
Psalms 91 is beautiful, I'll admit. It was my favorite Psalm when I was a Christian. But it did not work for me. I know there are many who have something unusual happen in their lives that believe it was God looking out for them. But there are many more who have trusted God and not seen the fruition of their prayers and seen terrible things happen in their lives.