You can try being there about 30 min. B4 the suggested time to begin embarkation. It has worked for us.

Depends on the ship and the line. If you arrive early, you'll almost certainly have to wait before boarding, even after checking in. If you arrive later, you'll more likely find an emptier embarkation hall. Most people want to be on board in time for a free lunch, so after 2:30 is usually a better arrival time. Most ships want you on board an hour before sailing, which is normally around 5pm, but can be later depending on the embarkation port.

The port also makes a difference. I was on a Celebrity cruise recently from Port Liberty, NJ, and it seemed to take an age to get us onto the ship, primarily because you have to take a bus to the ship from the check-in area.

But on a giant ship like Allure of the Seas, you'll actually be on board from curbside to the ship in about 20 minutes regardless of when you arrive. So as I said, it really depends on the line and the ship. My experience is that NCL is a little more chaotic.

I always like to check in pretty much as early as I can. Our last cruise departed at about 5:30, with the earliest embarkation beginning at 11:00, I believe. We were at the port at about 10:45 and on the ship by 11:00.

It is so much easier and relaxing being one of the first on the ship - no trouble getting a porter to take your luggage, no wait to check in or to board. You'll have to keep any carry on luggage with you for a while because your cabin most likely won't be ready.

I take advantage of the almost empty public spaces to take photos and explore the layout of the ship. After eating lunch at the buffet, we check if our cabin is ready and if so, use the time to start unpacking if our luggage has arrived. Usually arriving so early does seem to ensure our luggage gets there very quickly.

By the time the muster drill starts, I'm usually all unpacked and ready to go out and enjoy the departure from port immediately after.

It really varies. I think that the port matters. Last year in Barcelona we waited forever, largely due to the rent an agent staff that spoke neither English, Spanish nor Catalan and seemed to understand nothing in any language. Their work resisted throughout our trip even to the point of my wife being pulled out of the disembarkation line because they messed up the credit cards when embarking. Other times, same line and we could hardly keep up, it moved so fast.