When considering the optimal duration for treadmill workouts, what factors should one take into account to determine the right length of time? Is it merely about personal endurance levels, or should external elements such as fitness goals, age, and even health conditions also weigh heavily in the decision-making process? Should beginners start with shorter sessions and gradually increase their time on the treadmill, or is it better to maintain a consistent duration from the outset? Furthermore, what are the implications of varying speeds and inclines on the total workout duration? How do factors such as interval training and steadiness in pace influence the overall efficacy of a treadmill session? And in the grand scheme of things, how does one strike a balance between maximizing cardiovascular benefits while avoiding injury? What recommendations exist from fitness professionals that may aid in crafting a personalized treadmill routine that aligns with individual aspirations and capabilities?