Do as the coach tells you. Most of the time we would spar to develop skills rather than win rounds unless of course your opponent brings it, then you can go full ******.
You should spar enough to make the guy respect you, I have guys trying to kill me in the gym but I go light enough not to kill him. I focus on trying to link combos together fluently and my defensive footwork.
:good I tend to hit hard in sparring, but not maliciously. But if someone's feeling the pace/shot, then we go easier until they recover, but while they recover we try to put them onto the ropes and touch them with light punches. No sense killing each other and no sense teaching each other that you get time to recover when you're hurt. In other words, we try to hurt each other but not injure each other. (totally different with beginners though...just focus on keeping myself safe and making them work)
If it's a noob I go hell for leather to prove I'm the man. If it's someone better than me I whine like a ***** so they feel bad about twatting me and only go easy. Then I twat them with a full power cross to teach them not to **** with me again.