Ever play Dungeons and Dragons? They have something called encumbrance rules. Very few Dungeon Masters pay more than scant attention to them. That is, until they figure out that the 40 pound hobbit is carrying a professional kitchen, an armory, and 3 tons of gold on his back. There are work-arounds for this, in terms of magic devices that allow it but even those have limits. As mentioned earlier the DMs would rather use the work-arounds and ignore the limits than do the hard mental work of keeping track of everything being carried and worn. Who can blame them? After all it is a fantasy situation, right? Wrong!!
As a reader I will probably notice if your one man space runabout has a battery of guns with the power of a spinal mount from a Deathstar. I’ll also notice if your squire is carrying a full-fledged smithy and a selection of swords, armor, bows, crossbows, cooking equipment and a kitchen sink on his pony, you know, the one he is riding? I will notice a lot of other things as well, if your naked character pulls out a heavy machine gun he has been carrying concealed in his escape from the WWII prison camp, I will be scratching my head.
This is a long way of getting to a point for writers. Make sure your character’s supplies are believable. If he is wearing a skinsuit to transfer between ships he had better not pull out a massive handgun. Well, not unless you cover for it. Mentioning his placing the weapon in a carryall before the crossing is one way to handle it. Mickey Spillane and a number of other writers of detective and spy fiction would mention that the suits they wore were tailored to hide the shoulder holster, etc. If your character is marooned on a planet for 6 months you had better mention that the local food is edible by humans or that he was able to find a cache of food. If the local food is edible there had better be an explanation of how humans can metabolize the alien vegetation, and how the human knew which local plants were not only nutritious but non-poisonous. If there is a city and interstellar trade it becomes easier, but how does he pay for food which has to be shipped in from off world? He certainly cannot pay for exotic imported food while hiding from other humans in the slums. Not unless he has a lot of money before going to ground.
OK, you stocked the ship with everything he needs to live and accomplish his mission. He has a pulse rifle he smuggled into the space station by hiding it under his dirty underwear which reeked so bad the customs agents weren’t willing to check under it. OK I’m not buying that one, but find a way. Now he is on a climate controlled station. Perfect 20c temps 24/7. Style for women is a wide belt and a pasty on the left nipple for available women, right nipple for married women. Men are wearing yoga pants with a beret. All our hero has to do is get to Guido’s headquarters and wipe the villain from the galaxy. How does he get his pulse rifle there? If he has it tucked into the waist band of his Yoga pants everyone will notice. And they won’t suppose he is just happy to see them. I know! He can hide it under his overcoat! I bet he doesn’t get two corridors before the station security personnel pick him up.
Yes I just gave ridiculous examples, or did I? While I will own the station clothing as made entirely from my imagination (yes I DO have a rather sick imagination) it isn’t far off of things I have seen before. Sadly, the examples of equipment carried and concealed are equivalent to things I have seen in Real Published Books(TM) from traditional publishing. Think about these things before you send that story off to the editor, your fans will appreciate it. If you don’t think about it you might never have much of a fanbase.