Routes change every patch. The reasons a route works do not. If you understand these, you can level any build without a guide and recover when a guide is out of date.
Resistances are the whole difficulty curve
Elemental damage in the campaign scales hard, and your resistances do not go up on their own. The single best predictor of whether the campaign feels fine or feels brutal is whether your resistances kept pace.
- Take resistance rolls over damage rolls on gear while leveling. A blue item with two resistances beats a rare with a damage mod you barely notice.
- Never skip a resistance quest reward. They are permanent.
- Check your resistances at the start of every act. Two minutes, and it prevents the most common "the game suddenly got hard" experience.
The corollary: if an act feels impossible, the answer is almost never "more damage".
Life and one layer of defence beat damage
The campaign is not a damage check. Almost nothing in it requires high DPS; plenty of it requires not dying.
- Flat life on every slot. It is cheap, it is available on every base, and it is the most reliable survivability you can buy while leveling.
- Pick one defensive layer and actually invest in it — armour, evasion or energy shield, whichever your gear and build support. Splitting across all three gives you three weak layers.
- Movement speed on boots is a defensive stat. Not being where the attack lands is the best mitigation in the game.
Keep your weapon current
Weapon damage is the one offensive stat that goes stale fast, because the base damage of weapon types scales with their level requirement. A weapon that was great at level 20 is actively holding you back at level 40, no matter how good its mods are.
Rule of thumb: if your weapon's level requirement is more than about ten levels behind you, replace it — even with a plain white base of the right tier.
Skill gems: fewer, better supported
Levelling a skill gem and its supports matters more than having many skills.
- One main damage skill, properly supported. Three half-supported skills do less than one fully-supported one.
- Level your gems. An unlevelled gem in a good build is a bad build.
- Keep one movement skill and one panic button. That is enough utility for the campaign.
- Quality from a Gemcutter's Prism on your main skill is cheap and always worth it.
Do not over-optimise the campaign
The campaign is a fraction of a character's life. Things that are not worth doing during it:
- Crafting. Materials are scarce, your gear will be replaced in an hour, and you do not know your final needs yet.
- Chasing a perfect passive path. Get to your keystones; the fiddly optimisation can wait for a respec at 70+.
- Full clearing every zone. Clear what is in your way and what you need for levels. Backtracking for the last pack is time you could spend in the next act.
- Buying anything expensive. Anything you buy at level 30 you will outgrow at level 45.
The exceptions: resistance gear, a current weapon, and movement speed boots. Those three are worth buying cheaply and worth going out of your way for.
Level gates, not zone gates
Being the right level for a zone matters more than which zone you are in. If you enter an act underlevelled, the mobs hit harder *and* give less experience relative to the danger — the difficulty compounds.
Two or three levels below the zone is fine. Six is a problem. When you are behind, clear one zone properly rather than pushing on; you will make the time back immediately.
Ascend, and take the quest points
Your ascendancy is a large power spike and the quest passive points are permanent. Both are easy to defer "until later" and both make everything after them easier. Do them when they become available, not when you get around to it.
What changes and what does not
Patches change zone layouts, quest ordering, which uniques are good, and the specific efficient route. They very rarely change:
- Resistances being the difficulty curve.
- Life plus one defensive layer beating damage.
- A stale weapon being the most common self-inflicted problem.
- The campaign not rewarding optimisation.
So when a route is out of date, fall back on the principles. ePOE's leveling tracker gives you the current route; these are what to do when it and reality disagree.