Thx Ken - I thought as much.
New knife depends on many factors....
If mine......first off the steel characteristics, blade thickness/profile & geometry and type of knife with associated "anticipated" application.
I always sharpen a new knife before use by the way - I have not yet received one NIB with an edge finished to my liking.
So with some serious re-profiling on a good unit without a mirror polish would be anything from 1 to a couple of hours - I relax - take it easy & never rush.
However my Yoshi SLD Gyuto was a near perfect edge and extremely thin behind the edge, with a solid grind - took me like 30 minutes.
Sometimes I spend more time contemplating what to do with the edge than actually doing it....sometimes I even sleep over it.....milling so many numerous combinations through my knocker....
But yes, I reckon there is no simple answer - each knife is really different, necessitating dynamic flexibility in your approach to achieve your goal - I actually do not pre-empt a time frame prior to starting a unit - I just sit down & get at it....I am not a pro sharpener so time is on my side.
Guess not what you wanted to hear, but that is how it is for me.....