I use fixed sprint lengths (3w) with fixed team members, and a backlog of time estimated items that the product owner prioritizes. I would not go back to not d

I use fixed sprint lengths (3w) with fixed team members, and a backlog of time estimated items that the product owner prioritizes. I would not go back to not doing this, as it allows focus (sales people fight to get things into the backlog and next sprint, rather than grabbing a developer directly). It discards out of the blue time estimates ("oh, maybe 3 months?"), by rejecting everything longer than the sprint. It also foster better developer-tester communication inside the team, already during development, which kills bugs earlier. We're currently 3 teams with 5-6 developers and 1-2 testers each, soon to split into 4 teams and 2w sprints. So yeah, bigger company, Agile killed a previous waterfall model with 2 month spec creation/review, 2-3 month development phase with developers being added and taken away during the time, and 1-2 months of testing, followed by bug fixing by developers that were taken out from other projects started by then.