M+10 vs M+15 in Midnight S1 — When to Upgrade Your Weekly Key

For most Mythic+ players, the question every week isn't “what dungeon should I run?” — it's how high should I push my key. M+10 unlocks the Myth-track vault. M+15 awards Keystone Master and the seasonal mount. M+18 is the last tier where vault rewards still scale.

This breakdown compares the two most-asked tiers in Midnight S1: the cheapest Myth-vault entry (+10) and the title-locking sweet spot (+15). Vault math, IO gain, deplete risk, and the cost trade-off if you're considering a boost.

What changes at +10 vs +15

At a glance, the per-key reward jump from +10 to +15:

Vault item level: +10 → 707 (Myth 1/6) · +15 → 717 (Myth 3/6) · +10 ilvl difference
End-of-dungeon drop: +10 → 701 · +15 → 708 · +7 ilvl
IO score per timed run: +10 → ~80 · +15 → ~175 · 2.2× more
ETA: +10 → ~25 min · +15 → ~30 min
Affix scaling: +10 has Bargain at default, +15 has Bargain + Guile (kicks fail = damage)
Title unlock: +15 timed = Keystone Master title + mount; +10 timed = nothing additional

The vault math

Your weekly Great Vault gives three Mythic+ choices based on your top three keys timed (not your best key — the bracket of your 1st, 4th, and 8th highest). Implications:

1 timed +10 → first vault slot at 707 (Myth 1/6)
4 timed +10s → second slot at 707
8 timed +10s → third slot at 707 — full Myth 1/6 vault
1 timed +15 → first slot upgraded to 717 (Myth 3/6) — 10 ilvl jump
1 timed +18 → first slot at 717 max (vault caps at +18)

The optimal weekly approach for most players: run 8 keys at the highest level you can time, period. Locking the full Myth 1/6 vault at +10 is the cheap, safe baseline. Upgrading any of those 3 vault slots requires timing a higher key once.

The deplete risk gap

+10 is the “floor” tier — affixes are soft, timer is generous, depletes are rare even for pugs. Most players reading this can pug 8× +10 in 4 hours with a ~90% timer rate.

+15 is where pugs start failing meaningfully. Industry-wide pug timer rate at +15 is around 50–60%. A depleted +15 = no Myth 3/6 vault, no Keystone Master progress, and the keystone drops back to +14 — meaning you spent 35 minutes for zero progress and now have to time +14 to even attempt +15 again.

This is the cost of pugging that nobody puts on the title screen. Resilient at +15 exists specifically to break this cycle — once you time all 8 dungeons at +15, your keystone floor locks at 15 for the rest of the season.

When to upgrade: a decision framework

Stay at +10 if:

You're on a fresh character and gear is below ilvl 695
You play 4 hours/week or less and want guaranteed weekly vault
You don't care about the Keystone Master title

Upgrade to +15 if:

Your gear is ilvl 700+ (Myth 1/6 from prior weeks)
You want Keystone Master title and the seasonal mount
You're aiming for higher milestones (Keystone Hero, Keystone Legend)
You have a static group with proven +15 timer rate above 70%

Cost comparison: DIY vs boost

Pugging a single +15 dungeon successfully (multiple group rebuilds counted):

Time investment: 60–120 minutes (including failed groups)
Success rate: ~50% per attempt for pug-tier players
Real cost: 2–3 hours of weekend or weeknight time

Buying a single timed +15 from us:

Price: $26 USD (lowest on market — /mythic-plus/15)
Time investment: ~30 min run + 5 min Discord booking
Success rate: 100% timed or re-run free

For 8× full vault at +10: $65 bundle — half-price vs buying 8 individuals. Most cost-effective entry point if you want guaranteed Myth 1/6 vault every week.

FAQ

Should I time +15 once or +10 eight times?

Both. One timed +15 gets you the title + mount + a 717 vault slot. 8× +10 fills the rest of the vault at 707. The combined approach beats either alone.

Does timing +14 help if I'm aiming for Keystone Master?

Only the +15 timer awards the title — completing +14 timed gives you nothing toward the achievement. But +14 IO contributes to your overall score, so it's not wasted if you're aiming higher.

What about +12, +13, +14 — are those worth running?

Sub-+15 keys are mostly stepping stones for IO score grinding. The vault rewards barely improve between +10 and +15 (they only jump at +14 → +15). If you're comfortable with +12, push for +13/+14 instead of stacking +12s.