I’ve been using Debian-based distros for several years now.
But I have no experience with Arch at all. So… what am I getting myself into with Endeavour OS? How are packages handled and is availability similar to the “apt” system in Debian?
More importantly, how do I intelligently handle a rolling release so I don’t break my install?
personal pacman is handsome, to convert apt you can read this 
https://wiki.archlinux.org/index.php/Pacman/Rosetta
Also is handy to know how keyring works in arch. if a keyserver is failing you need to know how to solve, but generally is fine.
other side there is a place calling aur that needs a good readout how it works. packages comes from everywhere. but is just learn debian and arch is different, but i dont see my self goign to debian pacman is generaly much quicker on the feed then apt.
I wont speak for anyone but myself; but to answer your questions:
You get (what I believe) is a quality OS that you will only need to install once just focus on the updates as the come.
EndeavourOS uses pacman as @ringo mentioned. I would do a little reading to familiarize yourself. But you can think of pacman as apt. There is also a graphical interface for updating and installing software.
I update weekly to keep my system current. Also, if you are unsure what is being updated, check out the Archlinux wiki or just ask here on the forums. Folks here are pretty chill!
Either way, good luck on your future EndeavourOS. (See what I did there?) LOL.
If you know apt-get, I do not see a problem that you can not handle pacman in arch-based distributions like Endeavour. In my opinion, it is even simpler. The package base in Arch is really huge and they are fresher, which in some cases may be useful. Once installed rolling-release and you will have peace of mind. And, of course, a little reading is a good thing; there is a lot in the wiki and on the web.
Cool, not everyone here has an immediate (smaller or larger) experience 
; you will quickly acquire it over time.
From my view, an easy roll-back (time-shift) to a prior working version seems a reasonable option to maintain. Would like to know if Linux experts agree.
So will Endeavour have access to the main Arch repositories as well as the AUR (in addition to any Endeavour specific ones)?
@marlowe221 EndeavourOS is rolling like Arch, so you have direct access to the Arch repo and the AUR.
Also from next week on you will have a wiki to fallback on.
Therefore, you will be able to enter this system peacefully and test it. You have nothing to lose and you can only gain.
Endeavour comes with yay which is a wrapper for pacman and let you install from the official repos AND AUR while using pacman you can’t actually install from AUR without downloading and building the package yourself. yay makes it super easy to install. say you want spotify;
yay -S spotify
not hard huh?
Everyone new to Arch Linux thinks it is hard but Arch is actually some of the easiest things to actually maintain. So when you have a distro like Endeavour that is basically Arch with an installer - the last “hard step” is removed and all that’s left is easy.
Also in a community like this - there’s no need to be afraid to ask “dumb” questions - if you’re new you should stay away from the Arch Forum until you learned some basic things unless ofc you’re a masochist 
Here on the other hand people are happy to help. Just go for it - and have some fun. I’m pretty confident you’ll like it. Good Luck
edit: lol how did I miss this post was a month old. I thought it was like a few days. well well
You are getting Arch Linux installed by endeavouros using a Calamares ‘holding-your-hand’ installer. Arch Linux has the very best documentation of any of the Linux Distros. Endeavouros removes the need to run through all of the command-line instructions of a straight Arch Install. At the end of it, endeavouros has a package called Kula (?) which tells you when your system has updates and offers to do the update for you. Most Arch users (including me) simply use ‘pacman’ for updates. There is another repository called AUR with user-built packages and there are a number of apps that check and update them. My favourite is ‘yay’ which is simplicity itself to install.
You will learn to love Arch Linux through endeavouros and will never want to go back to those inferior distros. Enjoy, as the cousins say.
Kalu, is a very nice package if you don’t decide to go the pacman way. I only use pacman to get an easy overview over availiable packages, and pamac for most other things.
https://endeavouros.com/docs/applications/kalu/
Sorry for butting in @davidw 
You will find that it’s a pleasure to use this system. A rolling release is very nice - one of my Arch installations here I made in 2011 and I never had to make a fresh install. Eventually a problem can arise but until now it always was manageable.
For example kernel 5.5.1 had some bugs that made a USB3 card in my pc non-functional. I needed no snapshot to correct this: it was sufficient to reinstall kernel 5.4.14 (and kernel headers as well). So I could go on. The day after kernel 5.5.2 was there and solved this problem.
You can be assured that problems are possible but rare.
Enjoy!!!
Newest point releases can have sole usb quirks or video related. Its not tou must asap update, having a lts adviceble if the newest dont work,yiu have always fallback. Is always dificult ti say sometimez new systemd kernel networkmanager can wait 3 to 5 days longer with some luck it is fixed
I agree with that. I’ve learnt my own lesson. Elsewhere you can read that some of us are having trouble with the wifi AC-3168 card. The latest kernels 5.5.1 and 5.5.2 will not recognise the card. I have installed the linux-lts kernel and the wifi works just fine (though I don’t actually need it, it’s good to have everything working, isn’t it). At the moment the linux-lts kernel is 4.19.101-l-lts, but the latest is in testing and that will upgrade it to 5.4.18-1. I’ve been too quick in the past to accept the latest upgrades. I’ve learnt my lesson!
Question: is there a driver for it in the AUR?