Habit is a sort of personal assistant, isn’t it? It takes care of things without you having to worry too much about it. It is perfect for menial, simple, repetitive tasks that still need doing.
In my bedroom, I have two switches. The left one controls the overhead light, and the right one the plugs for lamps and the light. But in my case, I have a wake clock plugged into it, so if I turn the right one off, my clock resets.
No matter how long I live somewhere, I still get confused sometimes. My hand may remember, but sometimes my brain gets in the way. So I put a label over the right one. Now I will never screw that up again.
Now, you might say, as I said to myself, that is so simple that should not be necessary. I won’t say that sentiment is wrong. But my brain, as you may imagine, is always whirring, and I was able to put that particular mistake out of the range of possibility, through a simple expedient.
As William James wrote, over a hundred years ago, in his outstanding book that I think everyone should reread (and which as I have commented, warrants reading several times, particularly his extended phenomenological treatment of the Self/Personality/Sense of I), no one is more miserable who has to make the same decisions over and over across a lifetime. Habit allows you to delegate the unimportant.