DotA 2 Tips: Warding

Warding

Radiant side, defensive warding:

Radiant side, beginning of the game.

Radiant side, defensive warding if any of your first tier towers are taken.

Radiant side, defensive warding, if any of your first and second tier towers have been taken.

Radiant side, aggressive warding:

Radiant side, aggressive warding, if any of the enemy's first tier towers have been taken.

Radiant side, aggressive warding, if any of the enemy's first and second tier towers have been taken.

Radiant side, aggressive warding, if any of the enemy's first, second and third tier towers have been taken in a single lane

Dire side, defensive warding:

Dire side, beginning of the game.

Dire side, defensive warding if any of your first tier towers are taken.

Dire side, defensive warding, if any of your first and second tier towers have been taken.

Dire side, aggressive warding:

Dire side, aggressive warding, if any of the enemy's first tier towers have been taken.

Dire side, aggressive warding, if any of the enemy's first and second tier towers have been taken.

Dire side, aggressive warding, if any of the enemy's first, second and third tier towers have been taken in a single lane

Don't forget about Roshan: Several heroes can take on Roshan with life steal from Vladimir's Offering:

Also don't forget that many heroes in DotA 2 can go invisible if they have enough mana or under the  right circumstances. To keep an eye on these squirrel-y foes, use sentry wards: