I always do a beverage service every hour - thats A SERVICE, not a bar cart...so on a five hour trans-con I do two bar carts after take-off, two water trays throughout the middle portion of the flight, and a bar cart before landing. Often all of our beverage services go unnoticed by passengers because 90% of the passengers are sleeping, or so engrossed in their book or movie that they dont even notive me slowly walking through with a tray of OJ or water...but even on short EWR-ATL flight I do a bar cart and a water tray