Sitting in a chair for long periods of time at work? Couch in the evening? Long car rides?

From now on, think about where your hips are compared to your knees while sitting.  Are they above or below?  You can improve your low back, hip, or knee condition just by avoiding sitting in a low sinking chair, which puts your hips below your knees, putting a constant stretch/pull on your low back and hip musculature and compressing your "knee joints".  Sustained posture like this, although it may feel comfortable at the time, will eventually lead to problems over time and is most likely contributing/worsening any low back, hip, or knee pain you currently have.  The same concept applies to driving, especially if you do it for long periods of time.

Although not always avoidable, just being aware can help you correct these postural situations in the future.