Any one who put they have never suffered narcosis obviously doesn't understand gas laws. If you have been diving then you
have suffered narcosis. It is just a matter as to what degree or perhaps to what extent you're clear headed enough to realize your not clear headed
On the more salient issue of at what depth you begin to feel incapacitated? Then there will be a thousand answerers. For me depth is not particularly relevant, it would need to read at what depth under what level of stress.
On an easy relaxed dive I have run independent 12s and shot some great video footage at 65m on air. I can recall all the details of the dive no problem. On a stressful dive I have been badly narked at 30m and in danger of doing something rely stupid on a 60m blue water dive.
There is no specific line in the sand but i prefer to dive an equivalent narcotic depth of not more than 25m on any potentially stressful dive. On an easy clear blue warm water dive Id happily go to 60 on air and draw the line at 70 but I accept the fact if something raises my level of stress I will be hard pushed to deal with it.
ATB
Mark Chase