PCs or major (heroic) NPCs -
Step 1. Character background: one to two hours - tends to run to the long end for Modern characters, as I research details as a I go (for example, for a heroic NPC I wanted to know the history of Italian paratroops in action during WWII so that I could get the events in his background correct).
Step 2. Stats: thirty minutes to one hour - higher level characters take more time.
Step 3. Editing: one to two hours - usually spread over several days or a week, as I will look at the character sheet, make a couple of small changes, and put it down about a half-dozen times before s/he's ready to run.
Minor (ordinary) NPCs -
Step 1. Stats: five to fifteen minutes - usually stas come first as they are created to fit a particular need, and I'll create stats for a whole group of characters to share (for example, all of the legionnaires and legionnaires first-class are Str2/Tou1 and have the same stats).
Step 2. Editing: five minutes - a relatively simple step.
Step 3. Character background: five to ten minutes - a quick sketch of background and personality traits that might become relevant to the PCs if they are interacting with the ordinary NPC (for example, born and raised in Hamburg, HY AA artillerist during WWII, worked as cab driver after war, joshing sense of humor, close friends with Willi Dinter).
For Wing and Sword, I spent about four hours creating ordinary NPC character sketches for a platoon of thrty-plus paratroopers (all Ordinaries), two hours on their platoon leader (Heroic) and another four hours each on their company CO and XO (both Heroic) - the latter NPCs took longer than the platoon leader as they are both older and more experienced (the XO is ninth level, the CO is eleventh level).