Welcome! I believe this got answered more promptly on the Discord, but wanted to add some further thoughts here since the conversation moved on there.
First, I would say that if you’ve hired only a couple retainers, you can certainly hire more! Even if they don’t bring all their henchmen adventuring, I generally see parties pretty quickly reach at least a 2:1 henchman:PC ratio, and potentially considerably higher than that. Wages add up, and hiring bonuses to boost initial loyalty, and gifts over time to secure it. And of those henchmen in turn lack equipment (they’ll have whatever came with their template, but that’s always missing something), so you’ll want to buy more for them.
If you have a sufficient number of henchmen, you can also hire specialists, and mercenaries. Bringing a sage onto standing retainer can save you money in the long run, it’s just a somewhat expensive proposition up front (and to a lesser degree, an alchemist, though if you have components you can provide and good samples to duplicate, that proposition is more attractive). Ruffians can turn up rumors and treasure maps on your behalf (though possibly they’ll run up legal fees you’ll need to cover). And mercenaries can guard your camp and escort you through the wilderness, a great aid if you run into large bands of brigands or orcs, or just want to keep your horses safe while you’re in a dungeon.
In terms of equipment, there’s likewise rather more options than just a nice suit of plate. Stocking up on large quantities of military oil, holy water, herbs, and war dogs is classic (and war dogs benefit greatly from spiked barding . . .). Silver weapons, heavy helms, adventuring harnesses, higher grade thieves’ tools, etc. all tend to be useful investments that fall outside the scope of starting gold but are reachable with the proceeds from a first expedition. Outfitting a party with horses is likewise quite expensive (and if you want to keep them alive, horses wear barding too). Securing donkeys to supply such a band, with barrels and saddlebags to carry the supplies, and handlers to tend them, will further run up the expenses. That gets expensive to stable in town, so buying a villa to live out of can be very attractive - especially when you can count it as a credit toward your monthly upkeep!
Overspending on upkeep expenses can make you seem more important than you are, super useful if you intend to dabble in politics.
If you use the masterwork rules, then masterwork weapons and ammunition and armor for everyone who can use them are invaluable. Even if not, you’ll ideally want to keep 2000gp on hand so you can hire a researcher to identify appropriate magic items. Poisons may not be easily available, but they’re very worthwhile to keep on hand. And each player probably wants to have at least 900gp set aside to cover spellcasting expenses, should he come back cursed, diseased, wounded, or dead (not to mention also needing to cover any such expenditures for his henchmen, and possibly even mercenaries). Alternatively, while you don’t seem to have enough for it yet, reserve XP spending so that you’ll come back at 2nd level if slain is quite handy as well.
And this all assumes you’ve already paid off the tax man or otherwise avoided needing to fork over the landowner’s half of any treasures recovered!
So on the whole, 2500gp doesn’t seem much to have saved up at all. I know I’d probably spend most of it, just as one PC, if that was my share - and the rest would be saved to cover wages on payday, insure my resurrection if slain, etc., lots of very concrete expenditures. Many of them will be individually fairly small, but magnified across the size of the group, and a variety of such expenses, and the budget gets very tight, very fast.