The Basics of Roaming

What Roaming Does

• Frees up XP
• Frees up Gold
• Keeps the other team on their toes / forced into defensive stance
• Gives good rune control
• Potentially leads to kills (when done well)

When to Roam

• Your team has a lot of heroes that need BOTH XP and GPM
• You are no longer useful in the lane
• e.g. your carry feels very secure, so you should go do something more productive
• e.g. your lane failed and as a last ditch effort, you are attempting to force another lane to win hard
• The other team has a very vulnerable lineup (e.g. weak lane comps, heavy carry comps, etc.)

Metrics

• Highly Successful Roaming = lots of kills, which keeps you leveled and gives you money
• Successful Roaming = your team has more space to farm (other team is forced to play defensively), you have good rune control, and then you are given space later on to catch up in farm (think of how Na'Vi supports work - very active early on, then given time to catch up)
• Failed Roaming = you are underleveled / died numerous times / given no time to catch up in farm

Necessities of Roaming

• Good Teamwork - if you roam and your teammates don't communicate well with you, you won't get much out of the roam
• Opportunity - you can't just roam whenever. You have to look at things like how far the lane is pushed, HP/Mana or allies and enemies, etc.
• Regen - going back to base often is a waste, so you need to be able to stay out and out longer. Having someone like Crystal Maiden can help due to her aura, getting a bottle can situationally work, otherwise you'll want some clarities and shit
• Smoke if your friend
• A lineup where you can be out of lane and it's beneficial
• Heroes that can solo / dual lane successfully
• Heroes that need the early levels and farm, whereas you do not
• The space to catch up on farm in the event you did OK or Failed (e.g. some jungle stacks to farm, a lane you can farm while others shift into gank mode, etc.)
• Heroes that can kill as a result of a gank

Examples

Traditional Roamers are heroes like Vengeful Spirit and Earthshaker. Even when they are drastically underleveled, they are incredibly good gankers. VS has one of the best level 1 stuns, ES Fissure is also amazing when used well.

Your lineup also should have 2-3 heroes that need the fast levels, gold, and can get kills from ganks.
Examples would be like: Shadow Fiend, Gyrocopter, Kunkka, Templar Assassin, etc.

• All of them have spells that benefit from fast levels
• All of them need farm
• All of them can net kills from ganks

Bad Examples would be stuff like: Anti-Mage, Spectre, etc.

• Both these heroes offer nothing in ganks except some decent auto attacks, but nothing that can quickly kill or help lock a hero down
• While both benefit from levels, neither has as much to gain from them as someone like Shadow Fiend
• Both would be better off if you helped them secure farm instead

You should also look at your other support. If you leave a Venomancer to babysit Anti-Mage, while you roam to gank for your mid Shadow Fiend and offlane Weaver, you might jeopardize your hard carry's livelihood. A support like Venomancer doesn't offer that much in terms of counter-initiation (if you leave them against, say, Centaur and Rubick), especially when paired with a hero like AM that has relatively minimal early game presence.

Modern Roaming

From what I see in tournament games lately, instead of sacrificing a hero to roam, you more often see two scenarios:

1. You have a jungler that can roam between safe lane and mid lane to set up kills, or at least harass them (e.g. Chen picking up a harpy to harass with Chain Lightning, or a Wildkin to Tornado a lane)
2. Your supports pick up smoke early on and roam to mid, or sometimes even offlane when there is an opportunity or the safe lane carry feels secure enough to solo (even if just for a bit)

Both these methods guarantee a bit more farm. Jungling can especially have a similar effect as roaming because you've freed up more XP.