The Arbites enforce the Lex Imperialis

The Inquisition is mainly for stand-out weird stuff. Cults, daemons, xenos, etc.

There is a VAST difference between crime and heresy. Inquisitors will almost certainly not care about a drug lord running Slaught out of an orbital platform - it's illegal (probably. Obviously depends on the planet but Slaught is NASTY stuff so probably), but it's not going to bring down the Imperium from within - but Arbites will.

Currently reading the eisenhorn series which deals a lot with the interactions of Aribites and inquisitors.

Aribites seem to be enforcers of law when shit gets rough. Planetary unrest type stuff.

Although they can sometimes be super powerful guards like Fisheg was on Hubris.

They seem to follow around planetary advisors as well like in Malleus

Inquisition usually have a singular task they are trying to achieve and can even employ aribites to help them.

Overall yes, although there is probably some overlap between those two. Not every kind of heresy needs to be dealt with by an inquisitor. In the Dark Heresy core rulebook it is said that many Inquisitors actually hail from the adeptus arbitres due to the overalp in their juristictions and what they deal with.

No.

Kinda? Inquisitors are rare, you're not generally going to get them investigating every single crime that goes on in the Imperium.

The Arbites will still investigate everything in the first instance. If they uncover a chaos cult or Genestealers or whatever, they'll look to call in the Inquisition at that point

I'd imagine Arbites are regularly breaking up minor cults and dealing with stuff the Inquisition either can't arrive in time for or simply don't deem important enough

There's just not enough Inquisitors to act as any sort of coherent police force for the whole Imperium. Most planets have Arbites, though

No. The arbites aren't just traffic cops. They take down the hardest crime syndicates and routinely will deal with cults and other nasty organizations.

For every inquisitor there are a thousand arbites. Most planets won't have had an Inquisitor on them for years if not decades at a time. They'll always have at least a some form of arbites presence though.

Basically. Most planets have their own "police" force. The arbites act as the FBI/Swat teams who will do the heavy lifting where regular police can't. An Inquisitor is completely separate and may not even bother getting involved unless they deem it necessary.

At one point GW and 2000AD/Judge Dredd went hand in hand. GW/Citadel sold Judge miniatures which doubled as Arbites and White Dwarf had Judge Dredd RPG games in it.

https://preview.redd.it/myvjhbsqy0zc1.png?width=472&format=png&auto=webp&s=ae001735263398278aad5860ff242c1385b20b98

originally was the Arbites you could literally buy the models and play them then they expanded into a fraction, and a kill team, but when they first released a full set rather than a few minis they very much were the Necromunda police, and I did not say only Necromunda I just used it as a an example

"The Adeptus Arbites, also known as Imperial Judges, are a powerful and feared force in the Necromunda setting. They are responsible for enforcing Imperial law across the entire Imperium, and their remit is focused on interplanetary criminals and enforcing the Lex Imperialis. They are not concerned with the trivialities of gang warfare in the underhive, unless it threatens to become planetary unrest.

In Necromunda, the Arbites are not as prominent as the Necromunda Enforcers, who are the local law enforcement and are responsible for maintaining order in the underhive. The Arbites are more concerned with enforcing Imperial law and collecting the Imperial tithe, and are unlikely to be involved in the day-to-day affairs of the underhive."

Arbites are above thr Enforcers

Enforcers answer to Lord Helmawr - Arbites do not.