There is nothing at all wrong with sticking with what works for you. Whether it is your running routine...workout schedule...whatever it may be if it is giving you what you need then stick to it! However if you want to change...if you want to push and pull yourself to a new limit, a new normal then it has to challenge you. It will not change you unless that challenge is there. Many times it's the challenge that causes us to back away. I'm encouraging you if you are staring down that challenge and deciding whether or not you can do it...lean into it! Let that challenge whatever it may be, change you!!!