While everything that can increase your level is described as a "Powerful Reward", not all powerful rewards are equal. In fact there are at least 5 different kinds of powerful rewards that are defined by their soft cap. If your overall light level is below the soft cap, the item can be from 1 to 5 more than your overall light level (or even more if you're doing an activity while significantly under-leveled). If you are above the soft cap, the item will be 1 more than your overall light level.

520 Soft Cap Rewards:

• Daily Strike, Crucible, Gambit and Heroic Adventure
  
• Weekly Strikes, Crucible, Gambit, and Heroic Story
  
• Ikora's reward for 20 bounties
  
• Clan rewards
  
• Spider's Heroic Bounty

540 Soft Cap Rewards:

• Nightfall
  
• Nightfall 100k Score

560 Soft Cap Rewards:

• Petra's Weekly Challenges
  
• Petra's Ascendant Challenge
  
• Iron Banner "Powerful" Bounties

580 Soft Cap Rewards

• Tier 4 Blind Well

600 Hard Cap Rewards

• Individual Clan XP contribution
  
• Prime Engrams
  
• Exotic Engrams and Quests

I haven't included where the raid rewards fit to avoid spoilers, but it's safe to say that the raid is very good for leveling.

Your current overall light level will determine if a reward will be a +1 or a +5 improvement to a random piece of equipment. There's no fixed optimum order in which to do things - it's a probability game. So you need to choose between pursuing a +1 or a +5 reward; whichever has the better probability of improving your overall light level.

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I'll provide an example of how this works in practice

This is my 558 Titan's highest level gear:

Primary 561
Energy 560
Heavy 562
Helmet 557
Arms 553
Chest 562
Legs 553
Class 559

A +1 reward will bring a piece of equipment up to 559, so only my Helmet, Arms, or Legs would see an improvement. If the Helmet went to 559, it wouldn't quite be enough to raise my overall light level, but if the Arms or Legs went to 559, that would make the difference and raise my overall light level.

A +5 reward will bring a piece of equipment up to 563, so every slot would see an improvement. If the Helmet, Arms or Legs went to 563, that would raise my overall light level.

So there's a 25% chance that a +1 would be Arms or Legs, and a 38% that a +5 would be Helmet, Arms or Legs. Given a choice, I should do a +5 next (though unless it hit on one of those 3 pieces of gear, I'll probably need more than one powerful reward before I see an overall power increase).

If you're trying to maximize your power level increases, you should do this math after every powerful drop to decide what reward you should do next. If you are in desperate need of a kinetic power increase, you can do an exotic quest to target that increase (Ace of Spades or Chaperone).

Also remember that this is all dependent on RNG; if your luck is bad you can get really stuck. I went almost an entire week waiting for a class item; eventually it dropped 17 levels higher from a +1 because everything else had had multiple drops.

Definitely! I have my prestige raid scheduled, which may get pushed back to a time for you to help =]

I need to knock out some other milestones for the week tonight as well

This should be correct. They capped exotic quest drops to the max of their relative release, iirc.

If there’s nothing else you actually want to do, it’s not exactly helpful.

But I’ve been having so much fun just playing the game, jumping through activities. I get a Prime Engram or two every play session, and those are always large jumps (or have been for me). They help a lot. So if you just want to play Gambit or whatever, you can still keep getting Powerful drops at a pretty decent rate.

But if you’re going to play JUST to get Prime Engrams, I’m sure it’ll be an exercise in frustration.

It'll probably be difficult but you can damage the enemies. Why not jump in with a blind group even if you know you won't finish?