To know beforehand: my dog is not "smart dog", I mean it's not especially attracted. Thus, after a mass attack of these small parasites this summer, radical measures: Shower, basket change and flea pipettes. Nothing in 2 days (and I see wide efficiency almost instantaneously, but you have to leave some time to be sure, so let's say 2 days). A pipette was enough and nothing for almost 4 months.
I further specifies that this is an occasional use and therefore without habituation, which may explain the effectiveness of pipettes. This may not prove to be the case in all dogs, for various reasons.