daily is overkill for a solo operation. weekly is the most i would do them. after a week they are still in pretty good shape. if i go 2 weeks they start getting pretty dull but they still cut fine.
heck back when i only mowed my own yard i never sharpened blades the whole season. i just put a set on and mowed all season before i checked them again. never had an issue of the blades not cutting the grass good.
i live in the south so we mow the grass shorter. the grass cuts easier when you mow shorter since the blade is stiffer the closer to the ground you get.
think about it though, if you sharpen your blades for your "home" mower once per season, how many times do you cut???About 30 right? how many lawns does your business cut per day??? i do near 15 on some days, so thats roughly half a season on a "home" mower per day!!!! hell, i change mine sometimes halfway through the day if its wet!