Dota – How does the Performance Index work

Everyone usually shares a single courier that a non-carry player should buy at the beginning and upgrade to flying as soon as possible. You can buy more couriers (as many as you want), but most teams only use one. In general, solo mid gets first rights to courier use, especially in order to get their bottle.

Other than that, it is generally not encouraged for you to bring items to yourself that you could buy at the side or secret shops, as they are close enough you can just walk there from lane. If you do bring something from base, only do so with essential items or "big"(expensive) items. Otherwise wait until you have multiple things to bring out. Ferrying 1 ironwood branch at a time to yourself ties up the courier and will make everyone rage at you.

From the Dota 2 wiki:

Experience in DotA 2 is given by a unit on the enemy team that dies.

• Experience is equally shared by all allied heroes in a 1500 range.
• Hero kills outside of 1500 range will give experience to the killer. (I.e. Sniper's Assassinate, Invoker's Sun Strike, Zeus' Thundergod's Wrath or any summoned unit - Lone Druid's Spirit Bear, Nature Prophet's Treants, Broodmother's Spiderling and Spiderite)
• Denying an allied Hero does not grant experience to the enemy.
• Denying lane creeps grants 25% of their usual experience to both the enemy and the ally.
• Denying a player-controlled unit does not grant experience to the enemy or the ally.
• Neutrals killing lane creeps is considered the same as the enemy creeps killing them—it's not a deny, and gives full XP. You must deny the creep yourself to deny its XP.
• Neutral creep deaths grant experience to any nearby hero, regardless of the team that gets the last hit.
• Heroes take their share of experience even after level 25, even though they cannot use it.
• Observer Wards grant 100 experience when killed
• Ancients and Roshan acts as Neutral creeps with shared experience to all heroes within 1500 radius
• Bounty Rune grants experience to the hero that activates the rune (25 base exp + 7 exp/min)
• Hand of Midas active ability grants 185% of the transmuted creep's experience bounty to the hero that activates the item
• Tome of Knowledge active ability grants 500 exp to the hero that activates the item plus an additional 135 exp for each tome used by the team.