You've adapted to what you've been doing. I assume you want to improve your health--get stronger, lose weight, improve your balance and posture, etc-- and maintain your results. But if you continue to do the same thing over and over, you are not only going to plateau you are likely to back slide. So if you find that you are gaining weight but are working out regularly, it may be time to up the ante, or at least try a new routine.
You need variety to avoid over-use injuries and/or to cross train. I love water aerobics and swimming, but seldom make time for either. But boy when I do, it's a great workout and really challenges me. My body is doing something it's not accustom so I have to work harder. And that's good thing! If we only do what we are already capable of doing, we can't get stronger, or more flexible, or smarter. So try something new. Move your muscles and bones in different directions. Challenge your brain with new exercises. It's all good and your body will thank you!
You need some actual structure to your exercise routine. Most good trainers will tell you to have some sort of measurement to track progress. I do that with private training clients, my Tabata groups and Walk/Jog/Run programs. My group class peeps track progress more intrinsically, like how their clothes fit or how they can lift a child without hurting their back. So when I change a program up that's because I'm actually sneaking in some structure to your overall plan. I want you to keep progressing. See reason number 1.
You ask for help and I want to give it to you, even if you kind of don't want to hear it. This is where feathers get ruffled. We all know we need to exercise in some capacity, every day, right? You can very well do it on your own too. But if you come to me and hire me to do my job, I'm going to question your perceived obstacles. I don't have a hidden agenda or force you into training, it's a mutual agreement with both of us showing up and doing our parts. Now, if you just showing up gives you enough satisfaction, I'm fine with that. Really. Like I always say, anything is better than nothing. But if you sign up and want to achieve a particular goal and don't, I can only really help you if you're willing to explore why you avoid making the effort/changes I suggest. This is not easily answered. It can take lots of time to dig into what holds us back from what we say we want to achieve, be, do.
It's a seasonal thing. If you are a treadmill trudger then this may not apply to you, but for those of us who Take It Outside, I find a lot of us have SAW--seasonally affected workouts. I've asked a lot of the people I work with what they gravitate towards exercise-wise, based on the seasons. The consensus is cardio in the winter and more strength/flexibility/meditation work in the summer. It may have something to do with the temperatures or a yin/yang thing, but think about what you enjoy. Do you find you want to switch things up based on the season? Then you might just benefit from listening to you body.
So, there you have it. Those are some of the top reasons why it's good to change things up. What about you? See any changes in your future? Please share your insights!