Ok, blues answered.
- Upgrading an item costs 250 Valor for +5 item levels.
- Hellfire Citadel items, Dungeon loot, Baleful items, and crafted items can each be upgraded twice, costing a total of 500 Valor for +10 item levels.
- There is no hard weekly cap on Valor, but the sources of Valor are inherently not infinitely repeatable.
- Valor can be earned in the following ways:
- Mythic Dungeon (Valor awarded with dungeon completion, once per dungeon per week) – 300 Valor Points
- Complete the weekly Event quest from Seer Kazal (Pet Battle Event excluded) – 500 Valor Points
- Heroic Dungeon (complete your first random Heroic of the day) – 100 Valor Points
- Raid Finder wing (once per week per wing) – 150 Valor Points for Hellfire Citadel wings, 75 Valor Points for Highmaul and Blackrock Foundry wings
So, that's 300 * 8 = 2400 valor from Mythic dungeons, 500 Valor from the weekly event (there are now 8 including the Cata timewalking. 1 out of those 8 (pet battle) won't award it, 2 more out of the 8 (arena & battleground) require PvP). 100 * 7 = 700 Valor from heroics. 150 * 5 = 750 from HFC LFR. 75 * 7 = 525 from BRF and HM LFR. Maximum available per week is 4875 per week, which is 19.5 upgrades per week. The mythics are barely under half of that maximum.
There are 14 or 15 itemslots at two upgrades each, assuming no swap-in items and depending on whether you have an offhand or not, which means you need a minimum of 2 weeks to upgrade all slots. To upgrade all slots within those two weeks, you'd need 3500-3750 VP per week, which leaves 1125-1375 per week available to "ditch", at it were. Non-HFC LFR is worth a total of 525, so if you drop that, you have 600-850 leeway over the remaining options (daily heroic, HFC LFR wings, mythic dungeons, weekly event). That means, if you do all 8 mythic dungeons, you can drop any *one* of those categories (if you have an offhand, you'd only be able to drop 6 out of 7 heroics or 4 of the 5 HFC wings) and still be fine, as long as you fully complete the other two.
If you aim for 3 weeks for a full upgrade instead, you'd need 2333-2500 VP per week, which is essentially just the 8 mythic dungeons, plus maybe a single heroic 5-man.
Basically, we're going to be running the ever living shit out of those mythics, which means we need a couple spare tanks (or alts, and those alts would have to run each mythic twice, one for main, one for alt).
Edit: If you have multiple gearsets to upgrade, your free-time has my deepest condolences.