I enjoy doing user testing as a moderator, i.e. usability testing, contextual inquiry, but it's also emotionally draining for me (I wonder why?) Currently I'm doing it only once in a while. Majority of my time is doing other non-customer facing researches. But I am considering increasing it. Or even doing this full time.
My question to my fellow user researcher is, if this is your main task, how many can you handle, say, per week, per month, without it being too exhausting for you?
Thanks,
Its entirely on topic: moderating is highly intense because if you are doing it properly you are watching users like a hawk - something interesting can happen in a fraction of a second - and you have to be alert enough to spot it.
As to the number of sessions you can do: its difficult to give a number.
The other criteria which drives available time is building enough analysis time into the schedule so you have time to think about what is going on, so if there's a pattern emerging you can ask 'better questions' to later test subjects using what you've learnt from the earlier ones.
