Noun
force of habit (countable and uncountable, plural forces of habit)
(idiomatic) an act that has been repeated to the point where the performance of the act becomes automatic
"Only force of habit will explain why people today do honor to Christopher Columbus." - New York Times, 1937
I go on living, more from force of habit than anything else. Robert M. Pirsig
The features of our face are hardly more than gestures which force of habit made permanent. Nature, like the destruction of Pompeii, like the metamorphosis of a nymph into a tree, has arrested us in an accustomed movement. Marcel Proust
He held out his hand most often in the little square—not to revive old memories, but simply from force of habit. Source: Internet
Meanwhile, humans continue practicing formerly magical rituals through force of habit, reinterpreting them as reenactments of mythical events. Source: Internet
In this case, the action (sitting on command) will have become a force of habit, and breaking such a habit would result in mental discomfort. Source: Internet
It’s funny how many of one’s daily actions in the kitchen are governed by force of habit. Source: Internet