In Guild Wars 2, there are factors that determine how a character fares in combat, and these are Attributes. They come in three types, Primary Attributes, which automatically improve with leveling, and Secondary Attributes and Profession specific Attributes, which must have points assigned to them by the Player upon leveling.
Since there is choice involved in Secondary Attributes and Profession specific Attributes, it is a good idea to put some thought into your decisions when leveling, and this applies to the Mesmer as much as any other Profession. There are 4 Primary Attributes and 5 Secondary Attributes available, and these are constant between characters, whereas Profession specific Attributes are unique.
Each Profession comes with a different combat style dependent on its Skills, for example some prefer melee combat to ranged, and others focus heavily on granting Boons to themselves and their allies, and as such it is important to know which Attributes to spend your points in, in particular in relation to the Secondary Attributes. In the case of the Mesmer, who casts Illusions and Clones to dazzle their enemies while trying to outfox them, this can be an important choice.
The Primary Attributes are Toughness, Precision, Power and Vitality. These are mostly self explanatory. Toughness increased the Character’s armor by one point per level, decreasing the amount of damage that penetrates through the Player’s defenses. Precision increases the likelihood of landing an Engineer Critical Hit, which deals significantly more damage and can be the deciding factor in a battle.
Power affects the amount of damage that each of the Mesmer’s attacks do, and is especially relevant in regards to pure attacks, in this case usually in melee combat. Finally, Vitality increases the amount of Health that the character has by 10 points per level, and since Mesmer’s like to use tricks to win their battles, they are usually quite weak in direct combat, so investing in Health may be a good idea.
The Secondary Attributes are more specific, and pander to different play styles. They are Boon Duration, Condition Damage, Condition Duration, Critical Damage and Healing Power. Again, the titles are indicative of what each Attribute does. Boon Duration increased how long positive Boons last, which is particularly important to the Mesmer. Condition Damage increases the potency of Conditions like Confusion, Poison or Bleeding.
Condition Duration increased the length of time a foe is inflicted with the Condition, which is especially useful for Conditions like Immobilized or Crippled. Critical Damage improves the damage multiplier on Critical Strikes, raising it above the base 150%. Finally, Healing Power affects how powerful any outgoing Healing spells cast by the Character are, be they for Healing themselves or allies.
When leveling up the Player will be given the choice of investing in a Trait tree, each of which has relevant Attributes associated with it that improve with the Trait, and this is the main way in which a character’s Attributes improve. However, certain Equipment and Consumables can also affect a Character’s Attributes.
In the case of the Mesmer, the Profession specific Attribute is Shredding Recharge Rate. This reduces the recharge time on all Shatter Skills available to the Mesmer. A Shatter Skill is a skill that breaks all Illusions and Clones that a Mesmer is using at the time and induces a secondary effect, such as Mind Wrack, which damages any nearby foes as the illusions come apart, or Cry of Frustration which inflicts Confusion on any unfortunate foes caught in the blast. These all depend on the amount of Illusions and Clones that the Mesmer is balancing at the time, so for Players that use these combat tricks often, putting some points into Shredding Recharge Rate would certainly be wise to allow them to use such Skills as often as possible.
The Mesmer is a Profession that focuses heavily on trickery, and as such uses a lot of Conditions to dazzle and disorientate its enemies. These range from Crippling, as inflicted by Illusionary Leap, to damaging Conditions such as Confusing Images, which as the name suggests, instils a foe with Confusion, damaging a foe each time they use a Skill. The Mesmer’s full prowess with Conditions is best seen in the Magic Bullet Skill tied to the Pistol, which can hit up the three targets and will cause Stunned in the first one, Dazed in the second target, and Blinded in third.
This can be devastating to a group of enemies, and is a very powerful attack. All in all, it’s clear that investing in Condition Damage, for Skills such as Confusion, would be useful. However, even more appropriate would be Condition Duration, as this could leave a Mesmer’s enemies at a disadvantage in battle for quite some time.
The Mesmer also has access to quite a few Boons, such as Swiftness with the Temporal Curtain Skill and Might with the Mirror Blade Skill. The Siren’s Call Skill of the Trident is similar to Magic Bullet, as it inflict one of three Boons. Boons come into play heavily for the Mesmer, as Clones and Illusions receive the same bonus from Boons that the Mesmer themselves does, so putting some thought into Boon Duration when leveling may also be worthwhile.
All in all, because the Mesmer relies on Boons and Conditions, it would be wise to upgrade the relative Trait trees accordingly. They are far from poor at combat though, and putting a few points into Critical Damage may not go amiss either if it suits the Player’s combat style.
Finally, the Mesmer does pack a few Healing Skills, both for the Player themselves and for allies, such as Ether Feast and Mantra of Recovery / Power Return, so if the Player finds that their character is taking damage often, investing in Healing Power may also be wise. The Mesmer is a relatively flexible Profession, so the details are up to the Player and the combat style that they have decided to favor with their Character. As a general rule, however, Boon Duration and Condition Duration are near essential to almost any Mesmer, and Condition Damage to a slightly lesser degree.