A warm up is arguably more crucial than the core lifts you will be doing during a training session.  When incorporating big, heavy movements or a high intensity circuit session a proper warm up can make or break how well you move and perform.  A solid warmup should prepare you for the movements upcoming.  This is achieved in a number of different ways, but should not last anymore than 15 minutes.

Cap your warmup at 15 minutes

Honestly, it shouldn’t even take that long.  In that time frame you can get a ton done, so get off your phone and get to work.  Start with soft tissue work (foam rolling), mobility drills (upper or lower body), dynamic work (prep for movements that will eventually be loaded) all while working on movement patterns that you’re not great at.

I always see a warmup turn into 30-45 minutes consisting mostly of chatter, resulting in a multiple hour gym sesh.  Aint no one got time for that.  After the 15 minutes, your blood should be pumping and the sweat on your shirt should resemble what you’d like like after multiple sets of deadlifts  Condense the warm up, get your heart rate up, work on your shittier movement patterns, then go crush your workout.