On acoustic guitar I tend to stay in the key of D for some reason. On electric guitar I keep basic: C, G, D, and A. The key of D minor is also real good for me. ↗
If you ask what is the single most important key to longevity, I would have to say it is avoiding worry, stress and tension. And if you didn't ask me, I'd still have to say it. ↗
I think we too often make choices based on the safety of cynicism, and what we're lead to is a life not fully lived. Cynicism is fear, and it's worse than fear - it's active disengagement. ↗