Attunement in Dungeons and Dragons 5e
What is Attunement?
Certain magic items have the prerequisite called Attunement before its magical properties can be used. Attunement is a bond between a creature and a magic item that is formed over a short rest. There is a limit of three items a creature can be attuned to at one time. You can’t attune to items of the same name. If you attempt to attune to an item while at your limit it fails. Not all magic items need to be attuned to.
That’s it, but if you want to read more, the Dungeon Master’s Guide(137-138) and Systems Reference Document (206) has more info on the full extent of what attunement is.
Attunement in Your Game
This should be a given but attunement limitations is up to the Dungeon Master, they can increase the limit or remove it all together.
If you can buy or choose your own magic items it can be daunting. The Dungeon Master’s Guide alone has over 150 magic items that require attunement, each with their own properties. This does not account for items from Xanathar’s Guide to Everything, or all other Supplements.
With so many magic items, a useful tool to find out what items magic items require being attuned to is donjon. At this time it only lists items from Dungeon Master’s Guide and Xanathar’s Guide to Everything. It list page numbers for the books and some of the magic items have the description when you click the name.
Attunment in My Game
I have in the mindset that a player should be a hero. They should be strong, a force to be reckoned with. With this in mind I have increased the limit to five. I also allow the users to spend gold to combine magic items. If they want a +1 suit of Adamantine Armor I allow it, but I do make the new item require attunement even if both of the items did not. I also allow my players to choose the items they want. I do not always have them pay gold for it but will create quest for the item, I do this for magic items in general. They may even just need to slay a monster or big bad that has the item that they want.
I have went on a bit and rambled. The first paragraph is what you need, the rest is just me rambling.