On a first clean, trad, I'd wipe everything down and do a spanking good job. Then on subsequent cleans I really wouldn't touch the frames; they're still clean.
At some later stage - maybe many months later - I'd think, 'Those frames need cleaning' and give 'em a wipe.
Some windows, without moving the ladder twice (which I didn't do), I couldn't safely reach to some parts of the frames with a cloth, but could clean the glass with a squeegy (the top part of a large sash windows for eg); so these frames I never cleaned.
I'm not an overly fussy window cleaner, and I don't get complaints (or it's very rare; I can't remember off-hand when my last one was (two years ago maybe?) - so my advice would be not to be overly fussy otherwise you won't turnover as much as you could.
I bet most customers don't even notice, and you will know your customers who're are picky and like a spanking good job.
I'm as fussy as my customers (within reason).
Anyway, I've got to go and get some new spurs; I've worn these ones out.
