I'm still relatively new at this and I'll start by saying that I never purposefully stayed over the time unless I was explicitly told to stay ("you can stay longer if you like" - "would you like to grab a bite to eat" or something similar). Even then, I never assume it's a free pass for me to stay longer than the agreed upon allotted time on every visit.
But there has been some instances where we don't realize that time's up until an hour or so after it's been up (I book longer appointments, as an hour or less seem far too short). When that happens I feel bad and I leave a tip which I would do anyways and I apologize for going over, and then I'm assured that it's no problem. That doesn't stop me from feeling kinda bad as I never want to impose myself or overstay my welcome.
So my question is this. Should I feel bad? Do I bare any responsibility for going over? Or is it all on the SP to manage her own time?