I've worked for free, essentially, professionally and personally.
As a full-time designer one can expect to be working on salary, and business hours aren't a thing really. How rough it is can vary from place to place, whether that's due to how a company/firm is run internally or the type of clients they deal with, or both. Some places you might be working 40-50 hours a week on average with crazy spikes here and there, which is chill as far as design goes...but others you might regularly be pulling 60+, or worse. I've seen it all, and heard it all from fellow designers. It's a rough field.
I've also volunteered my time and talents outside of work.