“Protect your own good in all that you do, and, as concerns everything else, take what is given as far as you are able to make reasoned use of it. If you don’t, you’ll be unlucky, prone to failure, hindered and stymied.” Epictetus, Discourses.
Know what is right and true for you, and make sure you never lose sight of it. Be wary of what may sap your strength (tasks, people, places) and be ready with a plan to replenish the good in you, if stocks are running low. Better still, keep the good topped up by doing something every day that keeps it front of mind.