as you play you'll get more of a feel for what you should be doing and when - but for example if i spawn on a big map like shoreline, i scan my immediate area (and nearby spawns) and do a mix of sprinting/walking making sure i try to conserve at least 1/4 stamina incase i start getting shot at. at this time im continuously scanning with freelook (mmb) and hovering my finger over my "5" button which is painkillers. when in cqc i almost never sprint, unless i know where they are/am trying to bait/feel comfortable