Is an $8 tip enough for 4 pieces of luggage?

My wife and I checked into Hyatt Regency in Long Beach and we had three regular large suitcases and a black and yellow crate (that you can buy at Lowe’s) as a checked bag as well. So there were a total of four pieces. I asked the bellman to take the bags to the room. I tipped the bellman $8 to put the four pieces onto the luggage cart in the lobby and take it to our room and take the bags off the cart and leave them just inside the door of our room. My wife thinks that was a very low tip. So I asked her how much would’ve been the proper amount and she said at least $10. I think the $8 was more than enough. What do you think?