It was personal, long long before my first professional session.
It seems that it's always been a part of my life. I couldn't even tell you what the exact first time was because even as a young child I experimented with acts of sadomasochism and bondage alone and with other kids my age.
I've never had a reason to yet and don't foresee one, but I do make special trips for sessions when travel and accommodations are provided by the client.
Depends on my mood as to whether I let them, but yes.
I've used some old ones for stuff for sissies to wear and I use it as a place to keep stuff like money.