Nothing in life is actually yours. Even our own lives were a gift. None of us asked to be born. Then we live until we die.
The time between our start and finish is where we explore, experience, learn, give, take, accumulate and serve. The longer we live, the more opportunity we get to gain and do these things.
Nothing is actually ours. Everything that comes our way is on loan for a time. We get to borrow and use as we see fit. We become the administrator of the things in life we get or get to do. And with that role we either squander or steward.
Make the most of your moments. Take care of what you have. Strive toward goals but be mindful of your thoughts, words, actions and motives. These are where you put stewardship (or squandering) into practice (or habit).