So, the game is nice to the players in that it lets them start with a ship; one of the most expensive, and impressive, possessions even a group of players is ever likely to have, but, even if you want another ship, it could take a considerably longer time to scrape up the resources to acquire one, leaving you a lone wolf, for possibly the entire game. I get that that can work for the players, but what about NPCs? How often should an NPC ship be a lone encounter? What's a good way to decide if they should actually have escorts?
I know that it could be sort of hard on the players, if they favored a smaller, less gun-laden ship, if every time they run into other pirates, or worse, they always outnumber the players, but then you might argue they made that choice. Should they expect to run into lone Ork cruisers, or should the bigger ships usually have escorts? Should the smaller ships travel in pairs? In my case, the ship in question is a potent cruiser, escorted by an armor-hauling destroyer (raider), so I wouldn't be too worried, but I don't know how often the other ships in the Expanse are as likely to be strapped for resources, like a dynasty might, and realistically travel alone, or if most encounters, in the void, should be against small groups of ships, rather than a lone light cruiser. Not sure how typical pirates, raiders, or the like, are likely to work, but I wouldn't want the space battles to seem even easier. On the flip, as I said someplace else, it seems unfair to step up everyone else, just because the PCs finally managed to succeed enough to afford more, but you don't want the challenge to disappear, either.
This was a ramble-on post, sorry. How do you usually justify the quantity size of enemy craft, in space battles, against your players, who may, or may not, have escorts, or even a non-combat (comparatively) vessel?