In short: Yes. An iCloud or iTunes backup is a great way to get a full workable backup of your entire device. This is part of the reason why iPhone users don't have any issues with buying a new phone every year, and they don't loose a bunch of productivity when doing so. That being said, I've included some complexities that I've found below for veterans of the Apple crowd.
Here's the official document on what gets backed up:
https://support.apple.com/en-us/HT204136
From my experience, Apple Pay(stored in the secure enclave), Watch Pairing, Bluetooth pairing, properly coded in-app purchases, and some app's log-ins aren't backed up, but other than that you can just backup and restore as much as you want. After iOS 9 and
app thinning, Apps don't automatically back up anymore, but the data in the home directory of the app does.
Full App Backups:
If you want to restore apps when you restore from an iTunes backup instead of re-downloading them, you'll want to download them separately to iTunes using the App Store through iTunes. Downloading apps that are important to you is a great idea if you want to re-install an app that is no longer in the App Store. For instance, you can't find
Hero of Sparta(1 2 or 3) in the App Store, but because I downloaded it to iTunes, I can still install it onto my iPhone as long as I use the same Apple ID as I used then.
If you want to do this automatically, set up automatic downloads through iTunes->Preferences->Store->Automatic Downloads-> and then check Apps. It can take up a lot of space on your computer, but when your favorite games get removed because a company doesn't want to support their game anymore, it's great to still have them.
App developers get to control what you backup, so if you do a bunch of in-app purchases, and the app gets removed from the App Store, you don't get to have that purchased content back. If the game is still in the App Store, most games/apps have a restore purchases button to get your stuff back.
On exploring backups:
You can use some tools to explore iPhone backups. I'm currently using iExplorer, but there are a bunch of other ones that do pretty much the same thing. These tools let you explore parts of your backup like text messages, voice mails, etc so that you can back them up and then delete them off of your device if you feel so inclined.
Note on iOS Versions:
If you think that you'll want to eventually restore to an earlier backup with an earlier version of iOS (let's say you want to try out a beta), ALWAYS go to iTunes->Preferences->Devices and then right click on your backup and click archive. That backup won't be overwritten anymore. This is
super important as you can't use a 9.1 backup if your device is on 9.0.2. You can restore to a 9.1 device from a 9.0.2 backup though.