How do I upgrade my party's weapons?

Question

I am a newish GM. Me and my party had about 5 sessions and I think it is the time to give them better weapons, but I could no find any tables for lvl 4 characters or anything similar. Is there a need to upgrade them, like giving extra damage or change the die from 1d10 to 1d12 or will it be balanced by their abilities? I know, that +1 weapons exist, but they look pretty weak and how does one make it +1 anyways? Any tips? (similar struggle with armor)

Answer 1

Power increases primarily come from class features, ASIs, and the proficiency bonus.

Generally speaking, a boring, mundane weapon in D&D 5e is perfectly usable from 1st level, all the way to 20th level. The main source of a character's power increase comes from class features, ability score improvements, and the increasing proficiency bonus:

• Class features add abilities to a character's repertoire that are usually combat applicable, and most classes have some feature that directly influences the damage output of the class (such as increasing the number of attacks or increasing damage die for things like the monk's unarmed strikes or the rogue's sneak attack), and some classes feature abilities that have primary utility in the social and exploration spheres of play.
• All classes offer opportunities for "Ability Score Improvements" at several levels. These ASIs increase an ability score, which can improve your effectiveness in combat of the particular score is relevant to combat.
• The proficiency bonus ranges from +2 at 1st level all the way to +6 at 17th, and it is added to your bonus to hit with weapons you are proficient with, and adds to your spell attack modifier and spell save DC.

With no magic items at all, at is expected that by 17th level any character can have at least +11 to hit/spellcasting modifier and a 19 spell save DC. These are very respectable, totally usable bonuses. So you don't need magic weapons to be competitive at any level.

You don't upgrade weapons (technically), you receive magic items.

There is no mechanic for "improving" mundane weapons as you describe. A weapon's damage dice are a fixed property of the weapon. That said, magic weapons come with various enchantments that affect weapons in different ways. The most boring of enchantments is the +X magic weapon. The most powerful of these weapons is the +3 magic weapon, which is already a Very Rare magic item. The enchantments can be more interesting and more powerful, but +3 is the highest bonus you see; more powerful weapons are given +3 and some other array of features. Now, I say "technically" in the section header because there isn't technically a mechanic for improving mundane weapons, but I quite often use "take the weapon to an enchanter" as one of the methods for distributing +X weapons to the party.

So how do I go about getting magic weapons into the hands of the party? I typically follow the "Magic Items Rewarded by Rarity" table in Xanathar's Guide to Everything. This guide contains detailed guidance on how many magic items of each rarity to give to the party during each tier of play, following the "Choosing Items Piecemeal" guidance:

If you prefer a more free-form method of choosing magic items, simply select each magic item you want to give out; then, when the characters acquire one, deduct it from the Magic Items Awarded by Rarity table in your notes. Whenever you do so, start with the lowest tier, and deduct the item from the first number you come across in the appropriate rarity column for the item, whether its minor or major. If that tier doesn’t have a number greater than 0 for that rarity, go up a tier until you find one that does, and deduct the magic item from that number. Following this process, you will zero out each row of the table in order, going from the lowest levels to the highest.

And you can get creative with how you actually distribute the items. I like to use a mix of "found it in a treasure hoard", "did a quest and was gifted a family heirloom", and "bought it from a magic shop", and many other methods. The method isn't all that important, just have fun and make it interesting. The important piece is balancing the distribution, so as not to give too many or too powerful items to the party too early, which the table described above is helpful for.

For further reading on distribution guidance, see chapter 7 of the Dungeon Master's Guide and chapter 2 of Xanathar's Guide to Everything. For magic item lists, see the previously mentioned chapters, as well as chapter 3 of Tasha's Cauldron of Everything.

Answer 2

Weapon upgrades are generally found^† magic items

Let's cover one thing first, upgrading weapons isn't necessary. The game will tick along perfectly well without any magic items. Don't get me wrong, finding magic items is fun an exciting, but the primary progression is your characters' features. Note that you're about to hit 5th level which is the first Tier Step (to Tier II) where features like Extra Attack and access to 3rd level spells warp the landscape a fair chunk.

The game's primary method for distributing better weapons, ie. magic weapons, is a part of treasure (See chapter 7 of the Dungeon Master's Guide). There's a set of Treasure Hoard tables you can roll on to generate loot (including money, gems, art items, and magic items), and description of magic items (many of these are also in the SRD). Xanathar's Guide to Everything also includes guidance around specific item distribution by tier of play (end of it's Chapter 2; Awarding Magic Items). As a simplification (and you get to have a lot variance in this), you might typically expect a party to have found 1–2 uncommon weapons (among their magic items) by the time they hit 4th level. Uncommon magic items include +1 weapons.

Now to cover that †. Part of the assumption and trope is that magic items are found in treasure hoard obtained when slaying the dragon (or other dragon stand-in). But you can construct any number of other means of awarding items to your players. Be that the suggested reward for a quest, either as a lump of treasure or by an entity enchanting an existing weapon. See also the (admittedly underdeveloped) Blessings and Charms towards the end of the DMG chapter of related such rewards.