This is where it all comes together.
The term carry on luggage has many meaning, depending on where you are and where you are going. If you are traveling within the USA, usually a carry on can be a 22″ suitcase. I say usually because that can really vary. And it depends on how you measure the suitcase. I have seen measurements given for the inside of the suitcase and called a carry on by those measurements. An airline does not care about the inside measurements. They care about the outside dimensions of your suitcase. Think of it this way, if you had to put your suitcase in a cardboard box how big would that box need to be to enclose the entire suitcase? That means it would have to enclose the wheels, the handles on top and the side, and any additional pull outs or extensions of the suitcase. The same applies to anything such as a duffel. How big would it be if it was filled completely.
Additionally you need to consider what you are allowed to take with you, what the airline allow. Where you may assume you get a carry on and a personal item, you might just find that is not always the case. With today’s method of ticketing, you might just find you don’t actually get to take a carry on suitcase with you. This can happen if you get a “cheap ticket”. Some of the least expensive tickets may have you boarding in the last group, and not guarantee you a carry on option. Some even actually state that you get a personal item only.
Also, as some planes fly completely full, there may not be space in the overhead compartments to put your carry on. I recently took a flight (11/2018) where part way thru boarding they announced that there was no more space in the overhead compartments. If you did not have a bag that could find under the seat in front of you, you could not bring it on. They checked it at the gate, and I’m not sure if people were charged.
This is just another way of saying beware the idea that you will have carry on luggage and actually be able to carry it on.
Now for that personal item. The size of the personal item can vary depending on the airline. Check your airline information when you book. Somewhere on their website will usually be the size limit for your personal item. I prefer either a small duffel or a soft tote. A backpack is also a good idea. The idea of a purse is great, but its best if its more like a tote/backpack where you can put necessities you need into it. Those necessities would include your 3-1-1 baggie of liquids, medications, electronics with chargers, wallet, passport, and any other necessity. There’s a difference between necessity and wanted items. Necessities would include those items you could not easily replace. That is why it includes medications, electronics, wallet, and passport. Necessities are by definition, a few items, not a lot of items. Necessities don’t include your clothes, shampoo, lotions, shoes, etc. Those are items you could replace if you had to. So necessities could easily fit inside a tote or backpack.
The reason I don’t automatically suggest a purse as a personal item is that some purses are stiff, they may have stiff stand up handles. This means it may not easily fit under the seat in front of you. If the handles are stiff and stick out, they may not fit under your seat without taking up room in the next seat area.
Now if you are talking about international travel, you may find that those measurements are not the same as for USA travel. For international travel, you will often find the measurements for carry on and personal items tend to be smaller. So that USA legal carry on may be too big for international travel. The same goes for a personal item.
Another luggage issue to consider is the airport you may go thru. If it is a smaller airport, you might find that don’t really get a carry on, but only get a personal item. Its best to check these details before you board, and maybe even before purchasing your ticket.
If you are going to someplace out of the way, think Alaska fly fishing, you might find that what you are really allowed is even less. I’ve been on specialty trips where your luggage is weighed. No overweight luggage at all in those cases. So its best to do some research beforehand.
I actually have a variety of suitcases. I have a smaller 19″ soft side 4 wheel carry on, a larger 22″ with 4 wheels hard case, then a soft side 22″ for international travel, then a large 22″ soft side case. Now you would think the various 22″ suitcases would all be the same size inside, but they are not. Somehow they are hold various amounts. I can’t really say why this is true, but I have found it is. Also be aware the difference in weight you will encounter with each suitcase.
A recent article I read suggested organizing your clothes using packing bags. I think I will try this, but before you consider it you need to make sure packing cases will fit inside your suitcases. Again, measure everything.