[2021] If this patch is an indication of what GGG can accomplish in 4 months, I never want to go back to the 3 month schedule

I'm really glad that you are enjoying the league!

It was three months of development for most of our staff, with some QA and a few last-minute changes by whoever was in over the Christmas period. I believe the reason it worked out well was our new development processes: https://www.pathofexile.com/forum/view-thread/2977334 (basically extreme scope control)

So the plan going forward is to continue the three months of development plus a month of QA and tweaks, but that still means that we're doing releases every three months (with the content ideally ready a month before each respective release). For example, 3.14 development started in mid-December, will likely be finished in mid-March and will likely release in mid-April.

And of course, not all releases are going to have endgame expansions alongside the league, so do expect the sizes of the releases to vary this year.