Originally Posted by
Capot
I recommend checking in online, partly to get the seat(s) you want, and partly so that you can choose the shortest queue, check-in or baggage drop. They'll always accept the bags at a check-in desk if you have already checked in.
This is pretty much my advice too, from both a passenger and as someone who has worked on check in (although the airline I worked for didn't force you to use a machine and still printed off boarding cards and bag tags at the check in desk and continues to do so).
I always try and check in online as soon as I can but as I usually have a bag I never bother printing off a boarding card. I never trust my printer to get the barcode right and don't really want to carry around an A4 sheet of paper anyway. I try and get one of the mobile phone ones to show that I have done it and can use the shorter line (if there is a dedicated online check in line). Either way it's irrelevant as I always request a new boarding card when I get to the bag drop desk anyway and have yet to be met with a no from any airline when I request a reprint. I like to have a physical card in case my mobile dies on me or I scratch the screen scanning the barcode at the gate/security. When flying an airline which charges for airport check in then I obviously print my own card.