Confused again...example time.
Let's say I decide to start out with an Ancient Sword, a Blaster Pistol, and a set of Armored Clothing - that'll run a total of 1,750 credits, plus 3,250 credits worth of miscellaneous other gear (since I presumably cannot just blow all of it on a gigantic spice binge). What would you suggest I use all that extra allowance to get?
Assuming the game lasts long enough for us to hit Knighthood, will I have to trade in the items I already 'own' to get the lightsaber? I had kinda pictured our sabers being the reward for a small quest, since we are supposed to craft them ourselves, rather than just being handed sabers by the Temple quartermaster.
It's a question of in-game credits vs. in-game justification for items.
See, 'trading in' is a misnomer. The vast majority - nearly all, really - of profits earned by Jedi/Padawan are expected to come back to the Order in some fashion or another. Think about Obi-Wan in Episode IV when he says "I don't recall ever owning a droid..." Despite the fact that R2-D2 is more or less his/Anakin's for 10+ years, he never considers R2 his property.
Your character probably WOULD trade in the ancient sword - he has a more effective equivalent, so it would probably be better-used in the hands of some Padawan. Regarding armor, it would probably be appropriated based on need. An assignment to a warzone would be more likely to involve Armored Robes, but they would be considered overkill for a peaceable assignment. Consider the however-many-credits a pool of requisition-able gear, rather than possessions. After acquiring a lightsaber, you can safely assume that you'll always have it. Other gear, however, is more need-based. That's part of the reason I'm looking to avoid crossover characters - AoR and EotE have Duty/Obligation, both of which provide more in-character justification for items a character will have for the rest of his/her career.
Is that 9000-something credits ALL a Jedi has to throw around at 150 XP? ....probably not. But a lightsaber is a major character-point, whereas a lot of other items aren't.
Armorer introduces a hard question, because they depend on their soak for defense, rather than whatever Parry/Reflect they might have accrued by that point. Most other Jedi are typically wearing Concealing Robes and happy with it.
Think of your so-far-acquired credits as a pool of purchasable items, rather than actual hard-and-fast owned items. A lightsaber is a defining piece of gear, whereas everything else probably isn't. At 150 XP, you can reasonably expect to have a lightsaber, plus whatever other gear the Order may or may not define as a necessity for whatever assignment you're on.