Just as iron rusts from disuse, even so does inaction spoil the intellect.
— Leonardo da Vinci

Iron rusts from disuse; water loses its purity from stagnation... even so does inaction sap the vigor of the mind.
Leonardo da Vinci inactivity quote

We always overestimate the change that will occur in the next two years and underestimate the change that will occur in the next ten. Don't let yourself be lulled into inaction.
— Bill Gates

I never worry about action, but only inaction.
— Winston Churchill

Use the losses and failures of the past as a reason for action, not inaction.
— inactivity quotation by Charles J. Givens