Ask yourself the following 3 questions.
Does the way you train match your goals?
You started running a few years ago. Once in a while if you feel like it. There's nothing wrong with that, but if you've already set a goal, such as running a certain distance, breaking your PR, or entering a competition, it's time to be a little tougher on yourself and maybe even stick to a schedule.
Do you enjoy it?
We'll be honest:sometimes we exercise because we think it should and should, but we also like it. If you notice that you are increasingly not going or that you enjoy it less, then it may be time to try another sport.
Are the times when you can exercise convenient?
As a student, you managed to do sports during off-peak hours with your cheap subscription. Now that you're working, you more often than not make it to exercise because your favorite classes are too early in the evening. Time to switch gyms?