Server reset is the term used to describe automated changes such as the daily reset of daily achievements and weekly reset of WvW matches. Most changes occur daily at 00:00, but a few changes happen at fixed times throughout the week. Some content is time-gated: this means that whenever it is completed it cannot be done again until the next reset, or fewer rewards can be gained from it until then.
Daily reset happens at 00:00. The following things are affected by the daily reset:
- Activity rotation
- Adventure rewards
- Dungeon reward chests. Diminishing returns for repeated completions of the same dungeon paths are also reset
- Festival-related interactive objects (Carving Pumpkin, Magic Snow)
- Hero challenge event rewards in the Heart of Maguuma
- Login rewards
- Open-world chests, including those at the end of most jumping puzzles
- World boss reward chests
- Zinn's Print-o-Matic
- Rata Novus Instructors, required for opening Zinn's chest
- Repeatable renown hearts (Ember Bay, Bitterfrost Frontier)
- Cold Resistance
- Daily — complete specific tasks in PvE, PvP, and WvW
- Daily Fractals — complete specific levels and level ranges in Fractals of the Mists
- Daily Bloodstone Fen — complete tasks in Bloodstone Fen
- Daily Ember Bay — complete tasks in Ember Bay
- Daily Bitterfrost Frontier — complete tasks in Bitterfrost Frontier
- Special events
- Halloween Daily — complete Halloween tasks
- Wintersday Daily — complete Wintersday tasks
- Year of the Ascension Part I, II, III, and IV — each have daily match completion achievements during the PvP League
- Clay Pot
- Glob of Elder Spirit Residue
- Grow Lamp
- Heat Stone
- Lump of Mithrillium
- Plate of Meaty Plant Food
- Plate of Piquant Plant Food
- Spool of Silk Weaving Thread
- Spool of Thick Elonian Cord
- Vial of Maize Balm
- Permanent rich veins of metal ore (randomly placed rich veins can be farmed once per instance, when they appear)
- Node farms
- Orichalcum Ore and Ancient Wood Log nodes
- Blooming Passiflora nodes
- Bloodstone Crystals and floating Unbound Magic orbs in Bloodstone Fen
- Petrified Stumps and floating Unbound Magic orbs in Ember Bay
- Winterberry Bushes and floating Unbound Magic orbs in Bitterfrost Frontier.
- Gathering nodes in your Home instance
- Gathering synthesizers in Guild halls
- Charged Quartz Crystal — converting 25 Quartz Crystals at a place of power
- All converters, including:
- Karmic Converter — converting karma into various items
- Fractal Reliquary — converting Fractal Relics into various Fractals of the Mists rewards
- Ley-Energy Matter Converter — converting Heart of Maguuma currencies into various rewards
- Mawdrey II — converting Piles of Bloodstone Dust into Gift from Mawdrey II
- Star of Gratitude — converting Empyreal Fragments into Generosity's Reward
- Princess — converting Dragonite Ore into Gunk-Covered Pellet
- Herta — converting Piles of Bloodstone Dust into Glowing Stone
- Sentient Anomaly — converting Piles of Bloodstone Dust and Dragonite Ore into Fluctuating Mass
- Sentient Aberration — converting Empyreal Fragments and Dragonite Ore into Fluctuating Mass
- Guild Trader — trades Guild Commendation for items
- Pact Supply Network Agent — trades karma for Pact Scout's Mapping Materials and recipe sheets
- BUY-4373 — limited amount of Deeply Discounted Fractal Encryption Keys and Discounted Fractal Encryption Keys
- Bandit Crest Collector — one Bag of Rare Gear
- Monday 07:30 — Guild mission rewards reset and new random missions given to guilds.
- Monday 07:30 — Raid rewards and progress reset. 
- Monday 07:30 — Black Lion keys may only be obtained from the level 10 personal story once per account per week.
- Thursday 20:00 — Map bonus rewards reset.
- Friday 18:00 (roughly) — World versus World reset for EU servers (the exact time varies from week to week). 
- Saturday 02:00 (roughly) — World versus World reset for NA servers (the exact time varies from week to week).
- Diminishing returns can prevent people from receiving reward and ground chests from world bosses.
- There is an additional minimum-time elapsed for some open world chests & for the daily resource nodes named above. Specifically, at least 5-15 hours must pass between the last time the 'node' was used, even if the daily reset time has occurred before then.