I have a few clients paying me for hourly IT support right now, but I want to move them onto monthly managed service agreements so I have predictable recurring revenue. Problem is I have no idea how to price it - do I estimate hours and multiply by my rate, or is there some other formula people use? I don't want to underprice and get crushed by needy clients, but I also don't want to scare anyone off when I'm still trying to build the business up.