"Life is long if you know how to use it." - On the shortness of life (Seneca)
Like any school of philosophy, Stoicism is rooted in a few foundational ideas for living a good life. First, we should focus our attention on discerning what is and isn't in our control. According to the Stoics, the only thing that is in our control is our judgment and voluntary actions. How we perceive things and how we allocate our attention, as well as our voluntary and intentional actions determine the quality of our life. In other words, we judge how "bad" an event is, when in reality, the event just happens, and it is our judgement of it that makes it good or bad. Now that we have discerned what is and is not in our control, the second foundation is to take complete responsibility for what we can control, and fully accept those that we cannot, especially our fate. In Seneca's book, "On the Shortness of Life", he says that how we use our time is up to us. We should not waste our limited time, and instead take action, as this is where meaning can be found. He also raises the idea of eliminating and avoiding distractions, as well as pointless ambitions without the pursuit of meaning and purpose. This brings me to the third foundation being acquiring wisdom and living through reason. This allows us to live in accordance with the universe and how things are supposed to be, not how we think they are supposed to be. A stoic is not surprised when things happen, as they know that what happened is the only way things could've happened, and it is their obligation to understand so that they may take action. Lastly, Stoicism is rooted in the acceptance of mortality. Stoics were very aware of their limited time on earth, as the philosophers who adopted this philosophy were not "full-time" philosophers, but were people who wanted to gain wisdom but ultimately to live their lives. To them, philosophy is meant to be a guide on how to live a good life, and that philosophy was not their whole life. Life is long if you know how to use it. Like any resource well allocated and utilized, the time we are given on this earth is enough, so long as we don't waste it, and choose what to do with it. Also remember, the time you enjoy wasting is not wasted time.