UPDATE 4/8/14 8.30AM Bungie has acknowledged the negative fan reaction to news that Destiny's raids don't supporting online matchmaking.
In a post on NeoGAF, Bungie writer Luke Smith said he could "understand everyone's frustration about the decision... and the limitations that this places on the activity's adoption at scale.
"That barrier to entry - the requirement that you get a group of people together and venture into something that is going to challenge your ability to work together (first) and your thumbs (second) - is a barrier I was willing to erect to preserve the activity goals."
Bungie expects "bleeding edge hardcore groups" to invest significant time in working through the raids, but that some people should be able to beat one in Normal mode within the game's first week on sale.
"Hard mode will take longer," he continued. "Once your group learns the encounters, you will be able to get through the Raid significantly faster than three hours."
Smith appeared to play down the fact that you'll need to befriend those who enter into a raid with you, stating just that the "disparate people who come together to try" a raid will be able to view it as "a team-building exercise".
Raids will be made easier to beat in several sessions by the ability to store your insertion points each week - meaning your group can break off and rejoin at a later time.
Progress and loot eligibility is then reset every seven days - meaning you can only gain rewards from an encounter once per week.
ORIGINAL STORY 31/7/14 10.30AM Destiny's six-person raids do not feature the option for matchmaking with strangers, developer Bungie has revealed, as it wants you to plan and tackle these tougher missions with friends.
Raids will be "one of the pillars of the game", late-game experiences that may last for a couple of hours.
"It's a bit of a risk," Bungie writer Luke Smith told IGN. "Because the activity requires you to have a group of five other friends to play with...
"The activity is going to take you and your group of five buddies into a place that you've never been. A place that you will return to frequently. And [it will] demand of you things you've never even really been asked to do in a shooter before."
Likening the raids to those of massively-multiplayer PC titles such as World of Warcraft and Everquest, Smith countered that the experiences will only unlock when players are deep enough into Destiny's campaign.
"I think Destiny's endgame begins as soon as you see the way the story ends," Smith continued, "as soon as you see the way we wrap up the sort of first piece of the adventure that we're going to tell.
"We want to set you back out into the world to keep going. We want to try to align your motivations as the player with the motivations of the character who you've been pushing around this world. So for us I think a bunch of the endgame starts right at level 20."
Destiny's exact level cap has yet to be stated, but Smith talks of content designed for characters higher than level 20 that you'll need to continue working towards.
Players who are level 25 will be able to access level 25 raids, for example, but even then may not be able to finish them. Multiple attempts may be needed to begin looting the event for better gear, then trying again.
Beyond that, there will be other reasons to continue playing even once you've exhausted Destiny's story - daily bounties, plus daily and weekly Nightfall activities with "extremely exotic rewards".