You can put a point in this spell earlier than suggested if you enter a teamfight and have the opportunity to turn multiple enemy heroes to stone, or if you need to quickly get in or out of a fight.
Starting
Start with it if you expect a high frequency of spells from enemy heroes on the lane.
A consumable for a burst of mana. Helps you cast spells on heroes and creeps and get your mana back without having to go to fountain.
The most cost efficient stats item in Dota 2. Useful in the laning stage to have an HP, mana, and damage advantage against enemy heroes. Can be used together with a Tango for double HP regen.
Early Game
A laning stage pick up that increases your mana pool, which is effectively also your HP pool. Also provides some much needed mana regen.
Start with Magic Stick if you expect high frequency of spells from enemy heroes on the lane.
An early to mid game item to defend against bursts of magical damage. Also provides some useful mana regeneration.
A core item that boosts the damage output of all your spells. Also provides mana regen and improves your mana pool through stats, which is effectively your HP pool. Builds into Meteor Hammer later in the game.
Mid Game
An upgrade for Kaya to have even more AoE damage and control alongside your spells, and do significant damage to towers. Also lets you clear creeps quickly together with your spells and provides decent stats.
A core item to lock down an enemy hero from high range to follow up with Gorgon`s Grasp and Meteor Hammer on them. Also improves your HP and mana pools. Gets upgraded to Gleipnir later in the game.
An early game pick up to use your tankiness to reflect damage back to enemy heroes. Particularly useful to gain some armor against heavy physical damage lineups.
An upgrade for Rod of Atos to lock down multiple enemy heroes from high range and set up for your Gorgon`s Grasp and Meteor Hammer on them. Also increases the AoE of Gorgon`s Grasp.
A core item to have a defensive tool against single target initiations and disables. Also brings you some mana when the reflected Snake returns to you.
Late Game
A core item to maintain your teamfight prowess and tankiness on the map more often by decreasing the cooldown of all your spells and items. Also improves your mana pool to increase your damage and effective HP pool.
A core item to have an instant disable against elusive enemy heroes and hit them freely. Also boosts your mana regen and mana pool, effectively making you more tanky with Mana Shield.
A core upgrade for Blink Dagger to get in the middle of teamfights with Stone Gaze and the rest of your damage and control spells. Also improves your HP and mana sustain every time you use the item.
An upgrade for Eul`s Scepter of Divinity to set up your Gorgon`s Grasp and Meteor Hammer stun on enemy heroes. Also lets you save an ally or dispel yourself and move to safety when in trouble. Also improves your mana pool through stats, which is your effective HP pool.
Situational
A situational item in the mid game when the dispel has great value to take silences and roots off yourself. Also improves your mana pool and regen. Gets upgraded to Wind Waker later in the game.
A mobility item to push yourself or one of your allies away from trouble, or close the gap on enemies. Also lets you push yourself over cliffs and impassable terrain.
A mid game pick up to have another tick of damage and movement speed slow every time you target an enemy hero with Mystic Snake. Also provides some much needed mana and HP pool. Gets upgraded to Khanda later in the game.
A mobility item in the mid game when you want to instantly get in the middle of fights with Stone Gaze and not get kited as easily. Also helps get on top of high priority backline heroes on the enemy team, such as Sniper.
A powerful defensive tool to reflect single target spells. Also provides a dispel on cast and makes you tanky with armor.
A powerful defensive tool to block single target disables and debuffs. Also provides effective damage through stats for universal heroes.
An upgrade for Phylactery when the break effect has great value against one or more heroes on the enemy team. Also increases your damage and tankiness through a greater mana and HP pool.
A situational item to avoid most disables on the enemy team and hit freely in fights without getting kited. Also improves your right click damage and tankiness through HP pool and magic resistance.
An upgrade for Vanguard that acts as a powerful disable against enemy right click cores with disarm. Lasts longer on ranged heroes. Also provides decent stats for more tankiness and damage.
