@stefanoStefano Marinelli I give clients the option to call any time, 4h minimum bill. Unless it's a specific pre-arranged blackout, like if I'm on a travel vacation...then it would be more, depending on my costs and inconvenience.

Used to do pager duty, billing 1h/normal work day, 3h for weekends/holidays... 11h/week. If pager went off, regular hourly billing for the resolution. That was great for getting maybe 2 pages per year.