Appendix B of the MTR tells us our recommended time limits.

For sealed deck it says:

Sealed Deck—20 minutes for deck registration and 30 minutes for deck construction. For sealed deck events that take place on the weekend of a new set release, 15 additional minutes for deck construction is recommended.

Prereleases (atleast those not 2HG) are run as sealed deck events. According to a literal reading of this text they are supposed to have 30 minutes for deck construction.
Most prereleases I've been to give more time then that and fall more in line with those 45 minutes for release weekend events. My guess is that's entirely fine.

So is there a reason that the MTR is out of sync with (my) reality here? Am i missing some strange factsheet that specifies the time limit for prereleases in an entirely different place?

It would make more sense to me if the MTR entry read:

Sealed Deck—20 minutes for deck registration and 30 minutes for deck construction. For prerelease events and sealed deck events that take place on the weekend of a new set release, 15 additional minutes for deck construction is recommended.

Any thoughts or links to places where this was discussed previously are welcome.

Hi Quinten,

Prereleases are run under Regular REL and those times are just a recomnendation to the TO. TO knows best what is good for their store and they know their player base.

As Prerelease is the first contact with the new set for many players and numerous players who attend prereleases also normally do not come into touch with organized play, it makes sense to give more time for deck construction.

Remember that at a Comp REL event, players are given 30 minutes to both build and register their decks, so in some ways, we're already giving extra time for Prereleases, and other Regular REL Sealed events.

Beyond that, Regular REL events without decklists allow continuous construction, so no one is locked into the choices they make in the first half-hour. Build a deck, see how it does, chat with your opponent, make some changes.

My LGS goes with 30m build, and its worked well for us. Experienced players appreciate that it gets them out of there at a reasonable time (or gives them time to grab food between the noon and 6pm events), new players are largely not agonizing over choices anyway, and can make changes later.

[deleted]

Edited Isaac King (April 22, 2018 03:58:14 AM)

At my Prereleases, I typically do around 50 minutes. With 20 minutes passed, I make an announcement like “if you haven't opened your packs, now is the time!”, at 30 minutes passed “If you havent decided what colors you want to play, this is a good time to decide” and at 40 minutes “Remember, if you're unhappy with your deck you can change your build after every round today.”

Originally posted by Milan Majerčík:

Prereleases are run under Regular REL and those times are just a recomnendation to the TO. TO knows best what is good for their store and they know their player base.

I agree with this sentiment. Being flexible to cater to local needs sounds sensible.
At the same time my education tells me that when there is a default option set for something too few people deviate from that choice. That makes it somewhat important that the default option is set in a way that suits the needs of the most.
I am not sure that's the case here. I am not going to claim it's a super big deal, but it got me curious.

Originally posted by John Brian McCarthy:

Remember that at a Comp REL event, players are given 30 minutes to both build and register their decks, so in some ways, we're already giving extra time for Prereleases, and other Regular REL Sealed events.

I had not considered the time it takes to fill out the played column on the decklist. So there's indeed a bit more deckbuilding time at prerelease then there is at competitive. Still that minor administrative task does not take up the 15 minutes extra that players receive during release weekend.
So functionally that leaves players at prerelease with less time than players have in the same format (without promo's) a week later.
Does that not sound at least slightly odd?