yes, definitely. if you don't check the schedule multiple times per day, you're bound to end up in an empty classroom or missing class. at least once a week, in my high school experience, a class gets moved in time and/or place, or gets cancelled entirely.

it's like train timetables, you know. yes, they're meant to be the same every day, but you'd be a fool not to check the updates before you go. that's just how it is in a large chaotic system.