I keep my front door locked at all times and lock the back door when I go out, and at night.
As a young woman I learned to defend myself, as I worked in the evenings and often had to walk home alone after midnight.
I still feel that the risk of being mugged or attacked by a would-be-rapist is greater for young women than for us who are over the age of 70, and I know I can scream very loudly indeed, if I should need to. And kick where it hurts most!
I cannot get into the habit of taking my phone everywhere with me, it doesn't fit into most of my pockets, and frankly, any attacker would grab it before I could call the police.
So no, I take reasonable precautions, such as making sure no-one, literally no-one , knows where I keep my household purse and visa card when at home- apart from that I don't worry about being able to cope and certainly not about burgulars - if I did, I should get a dog fast.