Likewise, there was a time when I was going to AMS regularly and got to the stage where one/two of the staff recognised me. But then I did not go to AMS for a few months and when I showed up again they DNKWIW.

As others have said, if you are a regular (as in business travel) then you are more likely to be recognised, but only in certain places. And staff turnover can mean that even if you did show up somewhere every week or so, they might be different staff on the shift.