If you already know this, have too much materials, and/or just don't care then you can skip this guide, but if you are a new light player or interested, just pay attention.

You don't need to upgrade your gear to a higher power unless it is necessary, like the case for game modes that require high power level: Iron Banner, Trials of Osiris, Master or Grandmaster Nightfall, and Raids and Dungeons (unless you're okay doing with a little bit less damage to enemies in these modes).

I know many people might not care as they already have a lot of materials, but those just starting off may want to save their upgrade modules until required. From what I learned from AFK farming and just general farming, high level loot gear still drops even if you are 750 or lower power level. This is the case for umbral farming that was done at the beginning of the Season of Arrivals. Many people farmed in forges at under 750 power level but still got 1050 umbral engrams for their farming.

For a further explanation on the loot mechanics of Destiny 2, most powerful engram drops range from 1 to 3 above your max gear level (sometimes bugs can make them more than 3 above, like prime engrams sometimes being 5 above). Each character has their own max gear level (you can see the max gear level on sites like Destiny Item Manager). If you're below max powerful power level (which is 1050 in the Season of Arrivals) Pinnacles will drop 4 to 5 above your max gear (sometimes even 6 or more above). But if you're above powerful power level (1050-1060 gear) then pinnacles will drop 1 or 2 above your max gear level. Basically a shortened version of this is that your gear level is basically based off of your maximum gear level and that's the loot that you get.

So let's bring in an example of what I'm talking about. So there's a Hunter that has a max gear level of 1040. But they are wearing armor and gear at around 1008 power level because they're AFK farming. If they were to somehow receive a powerful engrams, they would drop at around 1041-1045 power level. If they were to receive open-world engrams, they would drop at around 1037-1040. The hunter would still be getting higher and higher gear drops by receiving powerfuls and pinnacles that would increase the hunter's maximum gear level.

Pictured below is an image of my hunter at 1008 power and obtained a 1043 Aresenic Bite. The maximum power that my hunter had was 1040 before obtaining the Aresenic Bite.

Now you might be asking, "how much more damage will I be doing by going up power levels?" Well then I just got the data for you.

Using the same weapon (Arsenic Bite-4B) as shown above, I gathered data on 10 Arsenic Bite-4B bows, 6 without any damage perks and 4 with explosive head. The explosion in the explosive head along with initial impact does more damage than a bow without a damage perk. However, the initial impact of the explosive head seems to be around half of the damage of a bow without a damage perk. Note that this data was taken on PvE enemies and not PvP players, which may look very different. There is also a deviation/randomization of damage of weapons within Destiny 2 of around 1-2%.

This first graph contains the data from 6 Arsenic Bite-4B bows without any damage perks.


This second graph contains the data from 4 Arsenic Bite-4B explosive head bows' initial impact.

As one can see from both graphs above, the damage of weapons seem to be linear on PvE enemies. With the bows without any damage perks averaging an increase of 2.97 damage per power level. The explosive heads' initial impact data averaged an increased of 1.49 damage per power level, very close to half the damage of the non-explosive head bows.

The testing of damage of other guns also seem to be linear, some having slightly higher or lower damage per power level.

As mentioned in the beginning, there are some exceptions to when you should use upgrade modules.

• Iron Banner, Trials of Osiris - Although not necessary, you will do a lot less damage and receive a lot more damage.
  
  
• Master or Grandmaster Nightfall - If you're wanting to complete these nightfalls with much more ease, upgrading your gear is not a bad idea.
  
  
• Raids and Dungeons - Although not as severe in damage as the ones mentions above, you still do a little bit less damage. However, a dungeon that it does severely affect is the Prophecy dungeon, with some enemies being at max power level.

However, you can still choose to not use your upgrade modules for these gamemodes. This can be especially great for people that are very low on resources or masochists that go into Iron Banner or solo raids and dungeons at 750 or lower power (nobody does this, right?).

Let's say you want to infuse your gear due to one of the applied exceptions above. Some insight into the infusion mechanics might help you reduce your material usage.

Only Legendary or Exotic items can be infused to a higher light level and Rare, Legendary, or Exotic items can be used for dismantling in the infusion. Rare, Uncommon, and Common items cannot be infused to be a higher light level and special gear from holiday events like the Halloween Masks cannot be infused as well, since it does not have a power level associated with the gear.

Whenever you infuse a weapon, an upgrade module will be used, unless it is of the same weapon, like the example below of infusing an Anarchy into another Anarchy. When infusing the same weapon, it will only cost 1,000 glimmer instead of an upgrade module. (The note of "Base Power Too Low" means that the weapon you're using to dismantle for infusion has a lower or equal power to the weapon being infused, resulting in the inability to infuse)

The best place to get a lot of upgrade modules would be the season pass, it contains around 19 upgrade modules. After using up all those upgrade modules, the best person to gather upgrade modules would be from Banshee-44, located in the tower. He offers two weekly bounties that give Glimmer, an Upgrade Module, and planetary materials. He also has daily bounties that give enhancement cores which can be used to buy Upgrade Modules from Banshee, located at the Material Exchange tab,
If you don't have just enough of one type of material, visit Spider in the Tangled Shore, he usually offers Enhancement Cores, Legendary Shards, Glimmer, and cycles through 4 different planetary materials daily. The prices and materials needed to be exchange also change daily.
At certain difficulties, Nightfalls (located in The Vanguard strikes screen) can often drop multiple enhancement cores at the end of a Nightfall and is based off of how many Champions were killed. Killing all of them will result in a Platinum Reward.
Within Strikes and Nightfalls, there are many bosses that you encounter during the way. A special perk you can apply is through the Finest Matterweave, located in the inventory. By using this, the next time a boss is killed, an enhancment core will be dropped.
You can also dismantle gear that is masterworked or has high energy to give you enchanment cores. Dismantling a masterworked weapon, will give you around 7 cores while dismantling a masterworked piece of armor will give you 6 cores and 6 enhancement prisms. Masterworked exotic weapons will not drop enhancement cores and masterworked exotic pieces of armor will only drop an ascendant shard, 2 prisms, and 2 cores. Note that Year 1 weapons and gear may drop lower amounts of cores.

A place where you can get masterworked armor is the Pit of Heresy, dropping a masterworked pinnacle dreambane armor piece on each character each week. Resulting in a max of 3 masterworked armor a week which can be dismantled into 18 cores and 18 prisms.

In conclusion, stop wasting upgrade modules all the time. Just use them in moderation. I've seen and heard many friends complain about running out of upgrade modules and unable to afford them. Now you and I can share this guide to them and make sure they understand these Destiny mechanics. If this guide helped you at all, make sure to share this and give it a good rating.