What's said below, plus a few more
by TCIrish03 (2019-04-02 15:31:02)

In reply to: Perhaps a Hockey 101 question re substitutions  posted by El Kabong

1.) you develop an internal clock. 30-45 seconds and you know it's up. At younger levels though I remember going 1 min to 1:30 for shifts.

2.) Situational awareness. Don't change in your own zone. Don't change while backchecking. This gets tricky in 2nd period when you're further from your bench.

3.) when on the ice, you'd be surprised how easy it is to hear someone yelling from the bench. The boards and glass trap a lot of the sound in, unlike football or basketball.