There are several factors to consider when choosing the right luggage for your travel and how many you should take. Not all countries will have the same baggage size restriction as the US does. It pays to be aware of them too so you can take that into consideration when you choose your luggage and decide how many you will take.
My family and I have been traveling for more than a decade since we became employed in the airline industry. We actually have several luggages at home. I know, how can one have too many luggages. Well, to be honest, we have 2 hard cases and 3 soft ones and because there is 3 of us traveling, having 5 luggages in possession is reasonable. Why you might ask, here's why and some other tips to consider to choose the right luggage for your travel.
Decide on the number of bag you will carry according to the weight restriction and duration of your trip
That is why we have 5 but we don't all use them in one go. We only take a maximum of 3 checked ins and 1 hand carry (usually the hard case stroller to put our gadgets in) when traveling to Asia and Europe. However, it is a different in the US. If we know we are going to shop and not go to other states, we carry the usual allocation of 2 pieces of luggages. In this case, we take 1 hard case luggage for check in and the rest soft ones.
Consider the weight you are willing to spare for a hard case versus the soft one
If you are like me who loves to shop overseas, then consider carrying a soft case because you can spare the extra weight for your purchases. Do carry a small hard case trolley for any breakables you will buy to protect your fragile purchased goods.
Note how many of you are traveling
If it is just you then stick with the airline restrictions in the number of luggages and the weight. Usually, if you are a sole traveler, you tend to carry less stuff so a backpack or an overnighter will be right. If the whole family are traveling then it is okay to have few hard cases and few soft ones to balance the weight around.
Take note of the things you will pack
What you will pack in your bag will be a factor to note of since a hard case bag will be suited to protect fragile objects while the soft ones will be good to carry clothing stuff.
Take your pick.