The ancient steamer trunk was today's suitcase, but larger & more cumbersome for your man-servants to handle.  It carried the bulk of what you were taking to 'the Continent.'

Today's suitcase is usually smaller with efficiency-packing compartments and mobility features: rolling wheels, extendable handles and top/bottom 'grab handles.'

Most are prettier than mine (at right) which has been dragged down innumerable dirt roads, over rough cobble-stone streets, tossed on train & bus luggage racks all over the world for 20+ years, AND modified & repaired several times.

Today's day-pack is your suitcase's 'little brother or sister ' companion; a useful airline carry-on AND for carrying your daily essentials when sightseeing.

Anecdote: Camino de Santiago:
for my 600-mile trek across north-central Spain,  I purposely carried only a medium-sized day pack of essentials relying on albergues (refugios, nunneries & monasteries),  restaurants & cafes along the way. YTplaylist

Resist the belief that others gauge your travel skills or character & status on the newness, cost, or flashy look of your luggage. I never dwelt on 'others' luggage.

If they dwelt on mine, it was none of my business & I didn’t care. I doubt anyone, but thieves do care; fancy bags attract thieves.

Your travel belongings should be in these TWO

A. So, luggage has 4 parameters: 1) type, 2) size, 3) number, & 4) durability.

Some haul a couple of suitcases, a handbag/briefcase with other bags dangling off their arms. I have often seen those extra dangling bags left behind on a plane’s overhead, bus seat or hostel dorm floor.

Quote: “Take half the stuff and twice the money”, Susan Heller. 

1. Type of luggage?: my basic ideal combination: a suitcase & a  
          daypack. 

2. Size: suitcase & day pack?
    a) Dimensions & Weight:
      1) Suitcase: Maximum is about 62 in total of length, width, & height; weight: not to exceed 50 pounds (23 kg).
      2) Carry-on: must fit under the seat in front of you or in the overhead compartment (briefcases, small backpacks, or totes)   
        PLEASE remember --
          (a) You are Sharing the Overhead Rack: with ALL your fellow passengers. Please ....  don't hog that space with innumerable handbags, camera cases, etc.
          (b) Don't Block Your Feet: Anything you store under the seat ahead of you blocks available space for your feet which after several hours of walking at or riding to sites, you might want to stretch out.

    b) Luggage Hauling: Rick Steve's warns, (paraphrase): 'You might have to carry or roll your luggage over uneven pavement for several blocks, and then, sometimes, up & down multiple flights of stairs to your room at each hotel.

 The more travel experienced you become,
the more you whittle down & refine
what you carry ..... to the bare essentials.

Quote “Take half the stuff and twice the money”, Susan Heller.

Anecdote: Jim & Mary’s cruise luggage: 3 giant suitcases: on my only big cruise ship experience my friends had 3 giant suitcases that Joe could barely lift. I vividly recall his overweight face,  bulging red with exertion as he pushed, shoved, & dragged each one separately up 2 flights of stairs. (Note: they should have only needed one in their room, other 2 left downstairs) 

3. Number of pieces?  Clever Traveler’s designed ”capsule wardrobe.”

Anecdote: Jim & Mary's cruse luggage: 3 giant suitcases: (immediately above) 

    BEST Strategy: be a Fashion Clever Traveler by designing a ”capsule wardrobe.”: See a complete explanation immediately above under the “Wardrobe” section.      [jlk: Wardrobe]

Anecdote: MY solo independent traveler’s (SIT) perspective: Resist the belief that others gauge your travel skills, character or status based on your luggage & wardrobe. 

I never dwelt on others. If they dwelt on mine, it was none of my business & I didn’t care. I doubt anyone, but pickpockets do care.

4. Durability: most tech’s synthetics are essentially bombproof.

MY Solo independent traveler’s perspective: 
Independent travelers opt for high mobility, low volume & weight luggage because we have to transport it in a variety of vehicles, up & down stairs, down long airport concourses, long city streets, & rural village's dirt paths, and thru soft wheel-grabbing sand, etc.  

Anecdote: medium rolling soft luggage: I have traveled the world as a solo independent traveler [jlk: SIT - below]  for 20 years with the same soft, but rugged, medium size rolling dragging it down endless rough cobbled lanes & 3rd world dirt streets; my daypack on my back. 

Over time my rolling luggage looked worse & worse, occasionally needing repair, but presumably a less likely target of thieves. Ironically, it was so ratty that TSA frequently ‘randomly’ (LOL) inspected it AFTER I checked it. 😄. (TSA leaves a little note each time.)

Oh, & my wardrobe & ‘stuff’ always fit because I limited its contents.

Legendary novice tourist mistake: Too much stuff …. including me 25 years ago for several reasons:
    1) Older we get the more ‘necessities’ we require e.g. my dozen prescript drugs & vitamins for 90+ days. [pplk: Health: ]

    2) fashion-conscious tourists may sense a social mandate to ‘compete’ with other passengers’ large stylish wardrobes AND THUS, need large, multiple suitcases to carry it all. 

In fact, the fashion-clever traveler creates a "capsule wardrobe.” significantly reducing volume of wardrobe needing to be packed.  

Nordstrom: “WHAT IS A CAPSULE WARDROBE?”

https://www.nordstrom.com/browse/content/blog/capsule-wardrobe

    3) try to anticipate every possible minor & major need that might ‘possibly ‘ arise. Look closely at my Inventory list and you will see my examples of this.   [pplk” Resource: INV list]

Anecdote: Skopje, Macedonia’s hostel’s dull knives: kitchen knives were too dull for salads. So, I sharpened the knife on a brick wall outside the kitchen. Thereafter, I carried a tiny sharpening stone 3” x ¾”. Tiny, but useful. to make salads easily. also carried a very tiny emergency can opener cuz I once needed one. pik 

Note: If a minor crisis arises, your guide can help. Not their 1^st rodeo. 😃. 

Anecdote: CdeS: walking 300+ (?) miles a woman carried a separate toiletries bag with multiple forms of soap: hand, hair, body lotion, etc. I carried a couple of small hotel soap bars.

My Independent Traveler's Inventory List (of stuff):

Over time, I developed an exhaustive (obsessive) Inventory List [pplk: Resources: INV] that detailed every single item, it's quantity & its specific location in various individual compartments & pockets of both my day pack & rolling luggage.

My Inventory List was useful for several reasons:
    1. I knew exactly where each item was & could fast & easily find it.
    2. I could easily add necessary items or subtract unnecessary
        items based on each new trip’s climate, etc. (think So Mexico
        vs Antarctica)
    3. I could easily amend my last Inventory List for each future trips, 

A cruiser can do the same.