Make sure the person who is doing your electro is experienced with trans patients IMO. I heard some bad stories about people who got it done by electrologists used to just zapping a few hairs on menopausal women.
During upper lip electrolysis:
Me: "Stop a minute can I have a tissue please"
Her: "Here you go, you need a break?"
Me: "No, I just need the tears out of my eyes, please keep going."
I did a 4 hour session in my first electrolysis appointment in November last year. Did my whole upper lip and goatee area. It hurt like hell but I am pretty good with pain, I paid good money and I hate having to shave (it wrecks my skin) so I sucked it up. I strongly suggest investing in one of those stress balls. FYI I looked like Desperate Dan afterwards. Oh also don't worry too much about not being able to shave the area if your electrologist does it right all the hairs will be plucked out, you wont need to shave for a week or two in a cleared area. It was worth the pain.