How many depends on how many I have left in my boxes and where and when I'm going to fish.
As far as how many I produce when I tie, it depends on how you look at it.
Years ago I got a hold of a large chest of plastic drawers with slots to create dividers within each drawer.
Then I labeled each drawer according to fly pattern.
In the pattern drawer, I put the hooks in the model and sizes I need, and, depending on pattern and construction, prepared dubbing, hackle and wing feathers.
For sucker spawn, it's much easier. I cut up lengths of the yarn and have them ready to go and the hooks.
I keep my threads and several loaded bobbins on the pins on a recycled tape board from a paste-up room from an older newspaper back shop.
The pins are really aluminum nails with the heads cut off after they are nailed into the plywood. Mark up a grid for the nailing points, after measuring and accounting for the diameter needed for the spools, etc.
I also got some of the old newspaper paste-up counter (it's a light grey) and use that for my bench. It's wide enough so I can mount three vises and tie three flies, in varying stages, at a time.
While I'm waiting for cement to set on the initial wraps, I can start wrapping the next hook, etc.
It works out pretty well for knocking out what I need.
But I can't get anything done happily if I got to start from scratch with each fly anymore. And I kind of enjoy just spending a little time one night picking out hackles, or mixing up an amount of dubbing, or cutting up some wing cases, and then stocking up the drawers for the nights I feel like tying, which are always very close to when I need them.
This system really worked very well for me before I got married. Then it still worked, but my time at the bench was less. Then we had a daughter, and my time is even less. Then the area started being used as a general repair center for beheaded Barbies and other toys, and now it's a darned mess, so currently I got to spend a night or two or three cleaning it up so I can reorganize before I can even begin to sit down to tie.
Hope that helps.