I’ve put well over 120 hours into Borderlands 4 across three different vault hunter playthroughs, and I made every possible eridium spending mistake on my first run. I blew 1,500 eridium on slot machine spins that gave me nothing but useless common pistols, skipped side missions I later regretted missing, and had zero saved up when I hit max level and needed to reroll anointments for my build. This guide breaks down the best borderlands 4 eridium use cases so you don’t waste this rare, hard-to-farm resource on stuff that won’t help you progress.
Core Borderlands 4 Eridium Use Cases for Early Game Progression
When you’re still leveling up your first vault hunter, eridium is far harder to come by than it is at endgame. You’ll only get small drops from rare enemies, hidden chests, and main story mission rewards, so you want to make every single unit count. Unlock extra inventory slots first if you haven’t already – nothing slows down a playthrough faster than running out of space mid-mission and having to pause every five minutes to sell off junk loot. Each inventory slot upgrade only costs 50 eridium for the first 10 unlocks, and it’s one of the best quality of life upgrades you can buy early on.
Respec your skill trees for cheap while the cost is still low, too. For the first 30 levels, respecing your entire skill tree only costs 20 eridium, so you can test out different build ideas without wasting resources. You don’t want to lock yourself into a build you hate just because you’re scared to spend a tiny bit of eridium to adjust it. You can also spend small amounts of eridium to activate hidden fast travel points across each map, which cuts down on travel time significantly for repeat mission runs. You don’t need to overthink your borderlands 4 eridium use early on, as long as you’re not wasting it on useless purchases.
Endgame Eridium Spends That Boost Your Build Power
Once you hit the max level cap and start running endgame content, eridium becomes far more abundant, but also far more valuable for upgrading your build to tackle the hardest content. The priority shifts from quality of life upgrades to investments that directly make your character stronger, or unlock access to exclusive rewards. If you’re mapping out your borderlands 4 eridium use for endgame, rerolls should always be your first priority, even if you have a decent legendary roll already. I split my endgame eridium spending across four main uses, ordered by priority:
- Legendary gear rerolls: You can reroll the anointment on any legendary item for 500 eridium a pop, which is the only way to get perfect roll anointments that match your specific build. I’ve spent 3,000 eridium on a single shotgun roll before, and it was 100% worth it for my Moze splash damage build that now one-shots most endgame bosses.
- Eridium-infused permanent ammo upgrades: You can buy permanent upgrades that increase your ammo capacity for all weapon types, which is non-negotiable for endgame boss fights where you burn through thousands of rounds of ammo in a single run. These upgrades cost 1,000 eridium each, but they apply to all your vault hunters, so you only have to buy them once.
- Raids and endgame dungeon entry fees: Some of the highest-difficulty endgame content requires a small 250 eridium fee to enter, but drops exclusive legendary gear you can’t get anywhere else. If you run these with a co-op team, you can split the entry fee between all four players, cutting your individual cost down to just over 60 eridium per run.
- Cosmetic vault hunter skins and weapon trims: This is a low-priority but fun spend, especially if you want to show off a unique look in co-op lobbies. I only spend leftover eridium on cosmetics once I’ve already bought all the build upgrades I need, so I never waste resources I could use for power gains.
Eridium Uses You Should Avoid at All Costs
There are a lot of tempting eridium sinks in Borderlands 4 that are almost never worth spending your resources on, even if you have a huge stockpile saved up. One of the biggest mistakes that ruins good borderlands 4 eridium use plans is blowing all your stock on low-value purchases that give you no real benefit. Slot machine spins on Sanctuary are the worst offender by far – I tested the odds once with 2,000 eridium, and only got one usable legendary SMG that was 5 levels under my character. The official drop rate for usable legendaries from these slots is less than 2%, so it’s a complete waste of resources for 98% of players.
Low-rarity gear from eridium vendors is another trap to avoid. The green and blue gear these vendors sell is completely worthless, since you can find far better gear just looting basic enemies and chests as you play. You also want to avoid paying to skip side missions at all costs. That feature is marketed as a time saver for players who want to rush the main story, but you end up underleveled for later main story missions, and miss out on unique legendary rewards that you can only get from side missions. I skipped three side missions on my first playthrough and had to go back and complete them anyway when I hit a wall on the final boss fight.
How to Balance Eridium Spending Between Short and Long-Term Goals
You don’t have to hoard every single piece of eridium you find to make the most of it, but having a basic budget in mind will keep you from running out when you need it most. A solid borderlands 4 eridium use budget prevents you from wasting resources on impulse buys, while still letting you spend a little on fun stuff if you want. I split my eridium stockpile into three separate piles whenever I’m playing a new character: 30% for immediate, short-term needs, 60% saved for long-term endgame upgrades, and 10% for fun, low-priority spends like cosmetics.
Don’t spend every eridium you earn the second you get it – I made this mistake at level 25 on my first playthrough, and when I hit max level a day later I had zero eridium saved to reroll my legendary class mod. That set my build back almost 10 hours of farming eridium just to get the anointment I needed. If you play co-op, you can also split costs for things like raid entries and shared ammo upgrades with your team, which saves everyone a ton of resources in the long run. You don’t have to follow a strict budget to the letter, but being intentional about how you spend will make your playthrough way less frustrating.
At the end of the day, the best borderlands 4 eridium use strategy depends on your playstyle, but sticking to the tips above will keep you from wasting one of the game’s rarest resources. If you’re still new, focus on inventory and quality of life upgrades first, then shift your spending to endgame build upgrades once you hit max level. You can splurge on cosmetics or a few slot machine spins every once in a while if you have extra eridium saved up, just don’t make it your main spending priority. Whether you’re playing solo or running endgame raids with friends, being smart about your eridium spending will make your entire playthrough way more enjoyable.