For some providers I'm aroused on arrival, especially those I've met with before. I am reminded of how hot I find them and I am excited about what's to come. I'm usually aroused throughout but the extent of arousal will ebb and flow around what they are doing. As @big-n-tall says, when they're doing deep work, less. When they're running their hands over my ass, rubbing my neck, making deep moaning or grunting sounds (Ahhhh, Turcoman 🥰) that definitely gets me going. I also find if they are hard it makes me hard.