I'm sorry to say there are too many variables to properly answer that. It depends on the razor, your beard, your beard prep, and most critically, your stropping. Unfortunately, for many newbies the answer is "one shave" because they've screwed up the edge with bad stropping. In general, you could hope to go two or three months between honings but some people have to, or choose to, do a touch up after as few as ten shaves.

Also, it's a matter of degree of the touch up. The oft repeated rule for barber hone usage is that you should do a touch up AS SOON AS you notice ANY diminishment in the quality of the shave. This is because it takes much less effort to keep a razor sharp rather it does to sharpen a razor.