Well my experience with topical spironolactone is this: (Bear in mind i also used finpecia)
I used it twice a day from febuary until august, during that period of time i did see a few hairs come back where i was applying it (hairline and temples). I had to go on holiday for a week, and while there I didn't apply it at all, but continued with the finpecia. When I came back I noticed that several more hairs had come through on my left temple. Since then I have used it once per day, some days not at all, and have not lost any of those i saw come through.
I think spironolactone is not a topical you have to stick 'religiously' to, but it is helpful whenever you put it on, so probably the more the better. Although, I also think it MAY block pores which might explain why I saw those hairs come through after my hiatus from spironolactone, although I'm not sure what effect blocking pores has on hair growth.
Also, sometimes if i apply it in the morning, and at night rub an area I apply it to, I can smell the smell of the cream on my fingers... Not sure what that means.