Don't set charge limits, because odds are you can never get back to 100% battery charging ever again due to bugs (at best I get 99% now.)

Don't expect your games to "just work" - even if they have a green check box, expect to have to troubleshoot like you always have, almost certainly even more.

Memorize Steam button + X to open the keyboard, you're gonna need it.

Don't go anywhere without a charger unless you're playing a game that you know will last long on battery.

The more games you install, the more games you won't play. A giant SD card and a giant SSD just means you have more shit that you look at and feel guilty before you power it off because you can't decide what to play anyway (and that's a big factor for why our backlogs have been growing all this time even before getting a deck. Too many games, not enough time and motivation.)

Know that a USB-C dock is gonna have issues. You're gonna have to fuck with audio output settings each and every time you connect it, and sometimes when you resume it from sleep. It will not always gracefully recover when you unplug it either.

There's gonna be a refresh to the hardware before you know it, and you're gonna want that version.

It's too big to fit in your pocket, you basically need a backpack for it.

You won't need any kind of case, but a glass screen protector is a good idea.

The bottom plastic near the screws will crack from stress. It happens even moreso on the transparent model.

Expect very poor control schemes on any game that is not incredibly popular with official gamepad support. If you are patient and can setup the keybinds yourself you can do OK- but some games just don't work well with a controller, period.

Sleep mode drains battery like a motherfucker. It seemed great on release, but now I lose what feels like 20% a day, or more. This means the deck you set down Sunday night will almost certainly be dead by Saturday when you get back to it.

Games that have poor save schemes like what has been found in older RPGs can be frustrating to deal with, because if you pause your session and come back to it... you still need to grind to the next save point or lose your progress. This is in a non-issue in tons of games, but can be an issue sometimes.

Some games sync in-game settings to the cloud, and overwrite what you have on your deck or PC depending on what was last used.

If you use an SD card, sometimes it can take minutes to hours to provision the storage necessary to begin downloading and installing the game on said SD card. This is after it's properly formatted, no matter how many games have been installed and how much space is free. It's a great mystery.

There's hotkey combinations to turn up and down brightness. If you hold down the steam key long enough, it shows you many more of those combinations to do many more useful things.

When you're changing settings in a game, you can specify changing global settings or hit a slider to make it per-game profile. It's almost always better to change per-game profiles so your settings can be custom per game.

You can remote play on a ps5 incredibly well. Chiaki4deck is great.

Your GOG, Epic and other games do not work easily natively. There are fan projects like Heroic Games Launcher to have this functionality, but they aren't native to the system.

It's very easy to not have any of your steam playtime register with steam.

It's very easy for your steam playtime to suddenly display dozens or hundreds of hours from sleep mode being utilized in some games.

That's just what I can mention from personal experience.