A change in your routine is a good thing! Your body will get used to a regular stress, and soon it will require either more of something to get the same benefit or a different stress. If you are a runner and you seem to be getting stagnate in your training you can add in hills, speed work and fartleks to jazz up your workouts and jolt your body.
Cross training is also a great way to spice up your routine. Add in swimming, biking, stairs, weights, aerobics classes: whatever you want. This will switch up the stress you are putting on your body. It will also give your mind a new challenge!
Try something new!